[Win32] Possible ERROR_GRAPHIC_DISPOSED error during painting

[tmssngr]

Describe the bug
A couple of users reported following exception

org.eclipse.swt.SWTException: Graphic is disposed
	at org.eclipse.swt.SWT.error(SWT.java:4918)
	at org.eclipse.swt.SWT.error(SWT.java:4833)
	at org.eclipse.swt.SWT.error(SWT.java:4804)
	at org.eclipse.swt.graphics.GC.fillRectangleInPixels(GC.java:3003)
	at org.eclipse.swt.graphics.GC.fillRectangle(GC.java:2999)
	at smartgit.MH.a(SourceFile:347)
	at smartgit.ML.handleEvent(SourceFile:629)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4257)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1066)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1090)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1075)
	at org.eclipse.swt.widgets.Composite.WM_PAINT(Composite.java:1536)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4803)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5043)
	at org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3649)
...

It looks like Composite.WM_PAINT creates an Event with a gc with handle == 0. This can happen in this part of the Composite.WM_PAINT code:

				long [] phdc = new long [1];
				int flags = OS.BPBF_COMPATIBLEBITMAP;
				RECT prcTarget = new RECT ();
				OS.SetRect (prcTarget, ps.left, ps.top, ps.right, ps.bottom);
				long hBufferedPaint = OS.BeginBufferedPaint (hDC, prcTarget, flags, null, phdc);
				GCData data = new GCData ();
				data.device = display;
				data.foreground = getForegroundPixel ();
				Control control = findBackgroundControl ();
				if (control == null) control = this;
				data.background = control.getBackgroundPixel ();
				data.font = Font.win32_new(display, OS.SendMessage (handle, OS.WM_GETFONT, 0, 0));
				data.uiState = (int)OS.SendMessage (handle, OS.WM_QUERYUISTATE, 0, 0);
				if ((style & SWT.NO_BACKGROUND) != 0) {
					/* This code is intentionally commented because it may be slow to copy bits from the screen */
					//paintGC.copyArea (image, ps.left, ps.top);
				} else {
					RECT rect = new RECT ();
					OS.SetRect (rect, ps.left, ps.top, ps.right, ps.bottom);
					drawBackground (phdc [0], rect);
				}
				GC gc = GC.win32_new (phdc [0], data);
				Event event = new Event ();
				event.gc = gc;
				event.setBoundsInPixels(new Rectangle(ps.left, ps.top, width, height));
				sendEvent (SWT.Paint, event);

According to https://learn.microsoft.com/en-us/windows/win32/api/uxtheme/nf-uxtheme-beginbufferedpaint the call OS.BeginBufferedPaint might fail, return a hBufferedPaint == 0 and setting/keeping phdc[0] == 0. This case is not covered here.

To Reproduce
Unfortunately, not possible.

Expected behavior
Check the phdc [0] == 0 in Composite.WM_PAINT (and maybe silently accept it).

Environment:

1. Select the platform(s) on which the behavior is seen:

• • All OS
• • Windows
• • Linux
• • macOS

2. Additional OS info (e.g. OS version, Linux Desktop, etc)
   Windows 10

[tmssngr]

Maybe it also might be worth to check in GC.win32_new that the hDC parameter is != 0?