diff --git a/.gitignore b/.gitignore
index ee359c3a..54446e25 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,6 @@ api/node_modules
 api/env.local
 db
 attachments-db
+nextjs/.next
+nextjs/node_modules
+
diff --git a/api/controllers/ProposalsController.js b/api/controllers/ProposalsController.js
index 2a5f92f4..b57f928e 100644
--- a/api/controllers/ProposalsController.js
+++ b/api/controllers/ProposalsController.js
@@ -5,7 +5,8 @@ const ModelController = require('./ModelController');
 const Proposal = require('../models/Proposal');
 const Curriculum = require('../models/Curriculum');
 const Degree = require('../models/Degree');
-const { ForbiddenError, BadRequestError } = require('../exceptions/ApiException')
+const Exam = require('../models/Exam');
+const { ForbiddenError, BadRequestError, ValidationError } = require('../exceptions/ApiException')
 
 const fields = {
     "state": {
@@ -94,6 +95,8 @@ const ProposalsController = {
         const user = req.user
         const body = req.body
         const now = new Date()
+        const issues = {}
+        let has_issues = false
         
         // l'autenticazione viene controllata nel router
         // dunque l'utente ci deve essere
@@ -114,6 +117,7 @@ const ProposalsController = {
         const degree = await Degree.findOne({_id: new ObjectId(curriculum.degree_id)})
         if (!degree) throw new BadRequestError("Degree not found")
         const obj = {
+            state,
             curriculum_id: new ObjectId(body.curriculum_id),
             curriculum_name: curriculum.name,
             degree_academic_year: degree.academic_year,
@@ -136,13 +140,14 @@ const ProposalsController = {
 
         if (body.exams.length !== curriculum.years.length) throw new BadRequestError(`Years count mismatch`)
 
+        issues.exams = []
         for (let year=0; year < curriculum.years.length; ++year) {
             const year_exams = curriculum.years[year].exams
             if (body.exams[year].length<year_exams.length) throw new BadRequestError(`Exam count in year ${year+1} mismatch`)
+            issues.exams[year] = []
             for (let j=0; j<year_exams.length; ++j) {
                 const e = year_exams[j]
-                const exam_id = body.exams[year][j]
-                if (typeof(exam_id) === 'object') throw new BadRequestError(`invalid object id ${exam_id} at year ${year+1} position ${j+1}`)
+                let exam_id = body.exams[year][j]
                 let exam = null
                 if (exam_id && typeof(exam_id)==='string') {
                     try {
@@ -153,10 +158,10 @@ const ProposalsController = {
                     }
                 }
                 if (e.__t === 'CompulsoryExam') {
-                    if (e.exam_id !== exam_id) {
+                    if (!e.exam_id.equals(exam_id)) {
                         throw new BadRequestError(`Exam ${e.exam_id} expected in curriculum year ${year+1} position ${j+1}`)
                     }
-                    obj.exams[year].append({
+                    obj.exams[year].push({
                         __t: e.__t,
                         exam_id,
                         exam_name: exam.name,
@@ -167,13 +172,15 @@ const ProposalsController = {
                 } else if (e.__t === 'CompulsoryGroup' || e.__t === 'FreeChoiceGroup') {
                     if (exam_id === null) {
                         if (e.__t === 'CompulsoryGroup' && state !== 'draft' ) {
-                            throw new BadRequestError(`Exam not choosen in compulsory group`)
+                            issues.exams[year][j] = `L'esame di un gruppo obbligatorio deve essere scelto`
+                            has_issues = true
                         }
-                    } if (exam_id !== null) {
-                        if (!degree.groups[e.group]?.contains(exam_id)) {
+                        obj.exams[year].push(null)
+                    } else {
+                        if (!degree.groups.get(e.group)?.includes(exam_id)) {
                             throw new BadRequestError(`Exam not in group ${e.group} year ${year+1} position ${j+1}`)
                         }
-                        obj.exams[year].append({
+                        obj.exams[year].push({
                             __t: e.__t,
                             group: e.group,
                             exam_id,
@@ -183,6 +190,23 @@ const ProposalsController = {
                         })
                         credits += exam.credits
                     }
+                } else if (e.__t === 'FreeChoiceExam') {
+                    if (exam_id === null) {
+                        if (state !== 'draft') {
+                            issues.exams[year][j] = `L'esame a scelta libera deve essere scelto`
+                            has_issues = true
+                        }
+                        obj.exams[year].push(null)
+                    } else {
+                        obj.exams[year].push({
+                            __t: e.__t,
+                            exam_id,
+                            exam_name: exam.name,
+                            exam_code: exam.code,
+                            exam_credits: exam.credits,
+                        })
+                        credits += exam.credits
+                    }
                 } else {
                     assert(false,`unexpected type ${e.__t} in curriculum`)
                 }
@@ -221,6 +245,10 @@ const ProposalsController = {
             }
         }
 
+        if (has_issues) {
+            throw new ValidationError(issues,'Errore di validazione')
+        }
+
         if (state === 'submitted') {
             // ci sono abbastanza crediti?
             const curriculum_credits = curriculum.years.reduce((acc, y) => acc + y.credits, 0)
@@ -257,8 +285,8 @@ const ProposalsController = {
                 }
             }
         }
-
-        const proposal = new Proposal(body)
+        console.log(`creating proposal with body ${JSON.stringify(obj)}`)
+        const proposal = new Proposal(obj)
         return await proposal.save()
     },
 
diff --git a/api/models/ProposalSchema.js b/api/models/ProposalSchema.js
index c1eab766..3cb150d7 100644
--- a/api/models/ProposalSchema.js
+++ b/api/models/ProposalSchema.js
@@ -53,6 +53,7 @@ ProposalSchema = new mongoose.Schema({
     state: {
         type: String,
         enum: ['draft', 'submitted', 'approved', 'rejected'],
+        required: true,
     }, 
     date_modified: {
         type: Date,
diff --git a/frontend/src/modules/engine.tsx b/frontend/src/modules/engine.tsx
index 577f72e6..c4bdc024 100644
--- a/frontend/src/modules/engine.tsx
+++ b/frontend/src/modules/engine.tsx
@@ -191,7 +191,7 @@ export function useIndex<T>(path:string, query={}) {
     })
 }
 
-export function usePost<T>(path: string) {
+export function usePost<T>(path: string, onError?: (err: any) => void) {
     // funziona anche per Multipart Post
     const queryClient = useQueryClient()
     return useMutation({
@@ -201,6 +201,7 @@ export function usePost<T>(path: string) {
         onSuccess: async () => {
             await queryClient.invalidateQueries({ queryKey: [path] })
         },
+        onError,
     })
 }
 
@@ -424,8 +425,8 @@ export function useGetProposal(id:string|undefined) {
     return useGet<ProposalGet>('proposals/', id) 
 }
 
-export function usePostProposal() {
-    return usePost<ProposalPost>('proposals/')
+export function usePostProposal(onError?: (err: any) => void) {
+    return usePost<ProposalPost>('proposals/', onError)
 }
 
 export function useIndexProposal(query={}) {
diff --git a/frontend/src/pages/ProposalPage.tsx b/frontend/src/pages/ProposalPage.tsx
index c78c2dc5..25d62e36 100644
--- a/frontend/src/pages/ProposalPage.tsx
+++ b/frontend/src/pages/ProposalPage.tsx
@@ -1,4 +1,4 @@
-import React, { Dispatch, SetStateAction, useState } from 'react'
+import React, { Dispatch, SetStateAction, useState, useEffect } from 'react'
 import { useParams } from "react-router-dom"
 import {Button, ButtonGroup} from 'react-bootstrap' 
 import assert from 'assert'
@@ -20,14 +20,16 @@ import {FlashCard} from '../components/Flash'
 
 export function EditProposalPage() {
     const { id } = useParams()
-
     const proposalQuery = useGetProposal(id || '')
+    const curriculumQuery = useGetCurriculum(proposalQuery.data?.curriculum_id || '')
 
     if (proposalQuery.isError) return <LoadingMessage>errore piano di studi...</LoadingMessage>
     if (!proposalQuery.data) return <LoadingMessage>caricamento piano di studi...</LoadingMessage>
+    
+    if (curriculumQuery.isError) return <LoadingMessage>errore curriculum...</LoadingMessage>
+    if (!curriculumQuery.data) return <LoadingMessage>caricamento curriculum...</LoadingMessage>
 
-
-    return <ProposalForm proposal={proposalQuery.data}/>
+    return <ProposalForm proposal={proposalQuery.data} curriculum={curriculumQuery.data}/>
 }
 
 export default function ProposalPage() {
@@ -132,27 +134,27 @@ export default function ProposalPage() {
     }
     
     function ExamRow({ exam }) {
-        const query = useGetExam(exam.exam_id || null)
+        const query = useGetExam(exam ? exam.exam_id : null)
         if (query.isLoading) return <tr><td>loading...</td></tr>
         if (query.isError) return <tr><td>error...</td></tr>
         const real_exam: any = query.data
         return <tr>
-            <td>{exam.exam_code}</td>
-            <td>{exam.exam_name}
+            <td>{exam?.exam_code || '---'}</td>
+            <td>{exam?.exam_name || '---'}
                 {real_exam && real_exam.tags.map(tag => 
                     <div key={tag} className="badge ml-1 badge-secondary badge-sm">
                         {tag}
                     </div>)}
             </td>
-            <td>{exam.exam_sector}</td>
-            <td>{exam.exam_credits}</td>
-            <td>{{
+            <td>{exam?.exam_sector || '---'}</td>
+            <td>{exam?.exam_credits || '---'}</td>
+            <td>{exam ? {
                 'CompulsoryExam': 'Obbligatorio',
                 'CompulsoryGroup': exam.group,
                 'FreeChoiceGroup': 'A scelta libera (G)',
                 'FreeChoiceExam': 'A scelta libera',
                 'ExternalExam': 'Esame Esterno',
-            }[exam.__t]}
+            }[exam.__t] : '---'}
             </td>
         </tr>
     }
@@ -172,7 +174,7 @@ export default function ProposalPage() {
                 </tr>
                 </thead>
                 <tbody>
-                { exams .map(e => <ExamRow key={e._id} exam={e}/>) }
+                { exams.map((e,i) => <ExamRow key={`exam-${number}-${i}`} exam={e}/>) }
                 </tbody>
             </table>
         </Card>
@@ -209,16 +211,20 @@ export default function ProposalPage() {
     }
 }
 
-function ProposalForm({ proposal }:{
-    proposal: ProposalGet
+function ProposalForm({ proposal, curriculum }:{
+    proposal: ProposalGet,
+    curriculum: CurriculumGet,
 }) {
+    // curriculum serve solo per conoscere il degreeId
+
     const engine = useEngine()
 
-    const [degreeId, setDegreeId] = useState(proposal.degree_id)
+    const [issues, setIssues] = useState<any>({})
+    const [degreeId, setDegreeId] = useState<string|null>(curriculum?.degree_id || null)
     const [curriculumId, setCurriculumId] = useState<string|null>(proposal.curriculum_id)
 
     const degreesQuery = useIndexDegree()
-    const curriculaQuery = useIndexCurriculum(degreeId ? { degree_id: degreeId } : undefined )
+    const curriculaQuery = useIndexCurriculum(degreeId ? { degree_id: degreeId } : undefined)
     const examsQuery = useIndexExam()
 
     if (degreesQuery.isError) return <LoadingMessage>errore corsi di laurea...</LoadingMessage>
@@ -280,7 +286,10 @@ function ProposalForm({ proposal }:{
             </div>
         </Card>
         { degreeId && curriculumId &&
-            <ProposalFormYears proposal={proposal} curriculum={curricula[curriculumId]} degree={degrees[degreeId]} allExams={allExams}/>
+            <ProposalFormYears proposal={proposal} curriculum={curricula[curriculumId]} 
+                degree={degrees[degreeId]} allExams={allExams}
+                issues={issues} setIssues={setIssues}
+                />
         }   
     </>
 
@@ -302,11 +311,13 @@ function ProposalForm({ proposal }:{
     }
 }
 
-function ProposalFormYears({ proposal, curriculum, allExams, degree }:{
+function ProposalFormYears({ proposal, curriculum, allExams, degree, issues, setIssues }:{
     proposal: ProposalGet,
     curriculum: CurriculumGet,
     degree: DegreeGet,
     allExams: {[key: string]: ExamGet},
+    issues: any,
+    setIssues: Dispatch<SetStateAction<any>>,
 }) {
     const groups = Object.fromEntries(
         Object.entries(degree.groups).map(([group_id, group_exams]) => {
@@ -319,8 +330,12 @@ function ProposalFormYears({ proposal, curriculum, allExams, degree }:{
     // console.log(JSON.stringify({chosenExams,groups}))
 
     return <>
-        {curriculum.years.map((yearExams, number) => <YearCard key={number} year={yearExams} number={number} allExams={allExams} chosenExams={chosenExams} setChosenExams={setChosenExams} groups={groups}/>)}
-        <Submit proposal={proposal} curriculum={curriculum} chosenExams={chosenExams}/>
+        {curriculum.years.map((yearExams, number) => 
+            <YearCard key={number} year={yearExams} number={number} allExams={allExams} 
+                chosenExams={chosenExams} setChosenExams={setChosenExams} groups={groups}
+                issues={issues?.exams ? issues.exams[number] : null}
+                />)}
+        <Submit proposal={proposal} curriculum={curriculum} chosenExams={chosenExams} setIssues={setIssues}/>
     </>
 
     function initExams(curriculum: CurriculumGet): ProposalExamPost[][] {
@@ -390,13 +405,14 @@ function ProposalFormYears({ proposal, curriculum, allExams, degree }:{
     }
 }
 
-function YearCard({ year, number, allExams, chosenExams, setChosenExams, groups }:{
+function YearCard({ year, number, allExams, chosenExams, setChosenExams, groups, issues }:{
     year: CurriculumGet['years'][0],
     number: number,
     allExams: {[key: string]: ExamGet},
     chosenExams: ProposalExamPost[][],
     setChosenExams: Dispatch<SetStateAction<ProposalExamPost[][]>>,
     groups: {[key: string]: ExamGet[]},
+    issues: any,
 }) {
     const yearName = ["Primo", "Secondo", "Terzo"][number] || `#${number}`
 
@@ -419,7 +435,11 @@ function YearCard({ year, number, allExams, chosenExams, setChosenExams, groups
     </div>
 
     return <Card customHeader={customHeader} >
-        {year.exams.map((exam, examNumber) => <ExamSelect key={examNumber} exam={exam} allExams={allExams} groups={groups} chosenExam={chosenExams[number][examNumber]} setExam={examSetter(number, examNumber)}/>)}
+        {year.exams.map((exam, examNumber) => 
+            <ExamSelect key={examNumber} exam={exam} allExams={allExams} groups={groups} 
+                chosenExam={chosenExams[number][examNumber]} setExam={examSetter(number, examNumber)}
+                issues={issues?.[examNumber]}
+                />)}
         <div className='d-flex flex-row-reverse'>
             <button className='btn btn-primary'>Aggiungi esame esterno</button>
             <button className='btn btn-primary mr-2'>Aggiungi esame a scelta libera</button>
@@ -435,12 +455,13 @@ function YearCard({ year, number, allExams, chosenExams, setChosenExams, groups
     }
 }
 
-function ExamSelect({ exam, allExams, groups, chosenExam, setExam }:{
+function ExamSelect({ exam, allExams, groups, chosenExam, setExam, issues }:{
     exam: CurriculumExamGet,
     allExams: {[key: string]: ExamGet},
     groups: {[key: string]: ExamGet[]},
     chosenExam: ProposalExamPost,
     setExam: (e:string) => void,
+    issues: any,
 }) {
     if (exam.__t === "CompulsoryExam") {
         const compulsoryExam = allExams[exam.exam_id]
@@ -459,8 +480,9 @@ function ExamSelect({ exam, allExams, groups, chosenExam, setExam }:{
     } else if (exam.__t === "CompulsoryGroup" || exam.__t === "FreeChoiceGroup") {
         const options = groups[exam.group]
         const exam_id = typeof(chosenExam) === 'string' ? chosenExam : ''
+        const style=issues?{background:"yellow",padding:"1ex"}:{}
 
-        return <li className='form-group exam-input'>
+        return <li className='form-group exam-input' style={style}>
             <div className='row'>
                 <div className='col-9'>
                     <select className='form-control'
@@ -472,6 +494,7 @@ function ExamSelect({ exam, allExams, groups, chosenExam, setExam }:{
                         <option disabled value="">Un esame a scelta nel gruppo {exam.group}</option>
                         {options && options.map(opt => <option key={opt._id} value={opt._id}>{opt.name}</option>)}
                     </select>
+                    {issues && <div>{issues}</div>}
                 </div>
                 <div className="col-3">
                     <input className='form-control col' readOnly value={chosenExam ? allExams[exam_id].credits : ""}/>
@@ -510,19 +533,22 @@ function FreeChoiceExamSelect({allExams, chosenExam, setExam}:{
     </li>
 }
 
-function Submit({proposal, curriculum, chosenExams}:{
+function Submit({proposal, curriculum, chosenExams, setIssues}:{
     proposal: ProposalGet,
     curriculum: CurriculumGet,
     chosenExams: ProposalExamPost[][],
+    setIssues: Dispatch<SetStateAction<any>>,
 }) {
-    const poster = usePostProposal()
+    const poster = usePostProposal((err:any) => {
+        setIssues(err.response.data.issues)
+    })
 
     if (poster.isLoading) return <LoadingMessage />
 
     return <>
         {poster.isError && <FlashCard 
             className="danger" 
-            message={`${poster.error} [${JSON.stringify(poster.data)}]`}
+            message={`${poster.error}`}
             onClick={poster.reset}
         />}
         <ButtonGroup>
diff --git a/frontend/src/pages/UserPage.tsx b/frontend/src/pages/UserPage.tsx
index b7eeff29..39a486a0 100644
--- a/frontend/src/pages/UserPage.tsx
+++ b/frontend/src/pages/UserPage.tsx
@@ -93,6 +93,8 @@ function ProposalCard({proposal}) {
             })
     }
 
+    console.log(`proposal ${JSON.stringify(proposal)}`)
+
     const [state, stateClass] = {
         draft: ["Bozza", "secondary"],
         submitted: ["Inviato", "warning"],
@@ -101,16 +103,17 @@ function ProposalCard({proposal}) {
     }[proposal.state]
 
     return <div className='my-2 col-xxl-3 col-xl-4 col-lg-6 col-12'>
-        <Card title={proposal.degree_name} className="clickable-card" onClick={() => navigate(`/proposals/${proposal._id}`)}>
+        <Card title={proposal.degree_name}>
             <div className='d-flex justify-content-between'>
                 <div>
                     <span className={`badge badge-${stateClass}`}>{state}</span>
                 </div>
                 <div className='btn-group'>
+                    <Link className='btn btn-primary' to={`/proposals/${proposal._id}`}><i className='fas fa-file' /></Link>
                     {
                         proposal.state === "draft"
                         ? <>
-                                <Link className='btn btn-primary' to={`/proposal/edit/${proposal._id}`}><i className='fas fa-edit' /></Link>
+                                <Link className='btn btn-primary' to={`/proposals/edit/${proposal._id}`}><i className='fas fa-edit' /></Link>
                                 <div className='btn btn-danger' onClick={deleteProposal}>
                                     <i className='fas fa-times-circle'/>
                                 </div>