context notes list focus handling followup

- remember the last focused note-row in the contextPane
and, if possible, refocus it on shift-tab from sidenav, on
tab from the reader into notes pane, or on tab into the
notes list from the collapsible-section. Otherwise, focus the search input.
Per: zotero#4837 (comment)

- when a note is opened in the context pane, let shift-tab
from sidenave place focus on the links-box. That way,
it is not skipped during tab navigation.

- fix focus not entering note-editor on Tab from the "Go back"
button and instead wrapping around to the current tab

chrome/content/zotero/elements/contextNotesList.js

@@ -51,6 +51,8 @@
 		_numVisible = 0;
 
 		_hasParent = false;
+
+		_lastFocusedNote = null;
 
 		get notes() {
 			return [...this._itemNotes, ...this._allNotes];
@@ -118,6 +120,7 @@
 			this.addEventListener('click', this._handleClick);
 			this.addEventListener('contextmenu', this._handleContextMenu);
 			this.addEventListener('keydown', this._handleKeyDown);
+			this.addEventListener("focusin", this._handleFocusIn);
 			this.render();
 		}
 
@@ -152,6 +155,14 @@
 			}
 		}
 
+		refocusLastFocusedNote() {
+			if (this._lastFocusedNote) {
+				this._lastFocusedNote.focus();
+				return document.activeElement == this._lastFocusedNote;
+			}
+			return false;
+		}
+
 		_makeRow(note) {
 			let row = document.createXULElement('note-row');
 			row.note = note;
@@ -184,9 +195,23 @@
 			}
 		};
 
+		// Remember which note row was last focused to be able to return focus to it
+		_handleFocusIn = (event) => {
+			if (event.target.tagName !== "note-row" && !event.target.classList.contains("more")) return;
+			this._lastFocusedNote = event.target;
+		};
+
 		// ArrowUp/Down navigation between notes
 		// Tab from a note-row focuses sidenav, Shift-Tab from a note focuses the section header
+		// Tab from twisty icon into the notes list will try to refocus the last focused note
 		_handleKeyDown = (event) => {
+			if (event.key == "Tab" && event.target.classList.contains("twisty")) {
+				let section = event.target.closest("collapsible-section");
+				if (this._lastFocusedNote && section.contains(this._lastFocusedNote)) {
+					this.refocusLastFocusedNote();
+					event.preventDefault();
+				}
+			}
 			if (event.target.tagName !== "note-row" && !event.target.classList.contains("more")) return;
 			if (event.key == "ArrowDown") {
 				event.target.nextElementSibling?.focus();

chrome/content/zotero/elements/contextPane.js

@@ -327,9 +327,7 @@
 					return true;
 				}
 				else if (this.mode == "notes") {
-					// Tab into the notes pane
-					Services.focus.moveFocus(window, this._getCurrentNotesContext(), Services.focus.MOVEFOCUS_FORWARD, 0);
-					return true;
+					return this._getCurrentNotesContext().focus();
 				}
 			}
 			return false;

chrome/content/zotero/elements/itemPaneSidenav.js

@@ -388,19 +388,17 @@
 		handleKeyDown = (event) => {
 			if (event.key == "Tab" && !event.shiftKey) {
 				// Wrap focus around to the tab bar
-				Services.focus.moveFocus(window, document.getElementById("zotero-title-bar"), Services.focus.MOVEFOCUS_FORWARD, 0);
+				Zotero_Tabs.moveFocus("current");
 				event.preventDefault();
 			}
 			if (event.key == "Tab" && event.shiftKey) {
-				if (this._contextNotesPaneVisible) {
-					// Tab into notes pane to focus search bar
-					Services.focus.moveFocus(window, this._contextNotesPane, Services.focus.MOVEFOCUS_FORWARD, 0);
-				}
-				else {
-					// Shift-Tab out of sidenav to itemPane
-					Services.focus.moveFocus(window, this, Services.focus.MOVEFOCUS_BACKWARD, 0);
-				}
 				event.preventDefault();
+				if (this._contextNotesPaneVisible && this._contextNotesPane.selectedPanel.mode == "notesList") {
+					let focusHandled = this._contextNotesPane.selectedPanel.focus();
+					if (focusHandled) return;
+				}
+				// Shift-Tab out of sidenav to itemPane
+				Services.focus.moveFocus(window, this, Services.focus.MOVEFOCUS_BACKWARD, 0);
 			}
 			if (["ArrowUp", "ArrowDown"].includes(event.key)) {
 				// Up/Down arrow navigation

chrome/content/zotero/elements/notesContext.js

@@ -152,7 +152,10 @@
 
 		focus() {
 			if (this.mode == "notesList") {
-				this.input.focus();
+				let refocused = this.notesList.refocusLastFocusedNote();
+				if (!refocused) {
+					this.input.focus();
+				}
 				return true;
 			}
 			else {

chrome/content/zotero/zoteroPane.js

@@ -1138,14 +1138,11 @@ var ZoteroPane = new function()
 		// Shift-tab from the header into the itemsView.
 		if (Services.focus.activeWindow === window && this.lastKeyPress === "Tab"
 			&& (itemPaneLostFocus || contextPaneLostFocus)) {
+			// event.relatedTarget is null when moving focus in or out of <iframe> or <browser>
+			// so make sure to not refocus tabs when focusing inside of note-editor or reader
 			if (receivingFocus) {
 				Zotero_Tabs.moveFocus("current");
 			}
-			// event.relatedTarget is null when the reader is opened and we need a small
-			// delay otherwise the focus lands within the reader
-			else {
-				setTimeout(() => Zotero_Tabs.moveFocus("current"));
-			}
 			this.lastKeyPress = null;
 		}
 		// When focus shifts, unless we are inside of a panel, save