Always show scrollbars, ensure that timer is stopped

Under HiDPI, the canvas keeps going back and forth seeing if it needs scrollbars and sometimes this leads to the resize event firing over and over again in a loop

src/base/canvas.cpp

@@ -447,7 +447,8 @@ namespace Wisteria
     Canvas::Canvas(wxWindow* parent, int itemId, const wxPoint& pos, const wxSize& size,
                    const long flags)
         : wxScrolledWindow(parent, itemId, pos, size,
-                           flags | wxBORDER_NONE | wxVSCROLL | wxHSCROLL | wxFULL_REPAINT_ON_RESIZE)
+                           flags | wxBORDER_NONE | wxVSCROLL | wxHSCROLL |
+                               wxALWAYS_SHOW_SB | wxFULL_REPAINT_ON_RESIZE)
         {
         m_watermarkFont.MakeBold();
         SetCanvasMinWidthDIPs(GetDefaultCanvasWidthDIPs());
@@ -709,15 +710,13 @@ namespace Wisteria
         {
         if (m_delayResize && m_blockResize)
             {
-            if (m_resizeTimer.IsRunning())
-                {
-                m_resizeTimer.Stop();
-                }
+            m_resizeTimer.Stop();
             m_resizeTimer.StartOnce(500); // half a second
             event.Skip();
             return;
             }
 
+        m_resizeTimer.Stop();
         m_blockResize = true;
 
         wxGCDC gdc(this);