Description Laurent Redor 2021-06-25 04:30:28 EDT

+++ This bug was initially created as a clone of Bug #573497 +++

Steps to reproduce:
* install the starter example
* select any element
* in the appearance tab, click on the "paint bucket" icon. Like, many many times, for 10s or more
* eclipse shuts down, the error log shows:

org.eclipse.swt.SWTError: No more handles
	at org.eclipse.swt.SWT.error(SWT.java:4749)
	at org.eclipse.swt.SWT.error(SWT.java:4638)
	at org.eclipse.swt.SWT.error(SWT.java:4609)
	at org.eclipse.swt.widgets.Display.error(Display.java:1240)
	at org.eclipse.swt.widgets.Display.internal_new_GC(Display.java:2650)
	at org.eclipse.swt.graphics.Image.getImageDataAtCurrentZoom(Image.java:1547)
	at org.eclipse.swt.graphics.Image.getImageData(Image.java:1370)
	at org.eclipse.swt.internal.ImageList.set(ImageList.java:365)
	at org.eclipse.swt.internal.ImageList.add(ImageList.java:52)
	at org.eclipse.swt.widgets.Button._setImage(Button.java:131)
	at org.eclipse.swt.widgets.Button.setImage(Button.java:891)
	at org.eclipse.sirius.diagram.ui.tools.internal.dialogs.ColorPalettePopup.<init>(ColorPalettePopup.java:185)
	at org.eclipse.sirius.diagram.ui.tools.internal.properties.DiagramShapeColorAndFontPropertySection.changeColor(DiagramShapeColorAndFontPropertySection.java:136)
	at org.eclipse.gmf.runtime.diagram.ui.properties.sections.appearance.ColorsAndFontsPropertySection.changeColor(ColorsAndFontsPropertySection.java:372)
	at org.eclipse.gmf.runtime.diagram.ui.properties.sections.appearance.ShapeColorsAndFontsPropertySection.changeFillColor(ShapeColorsAndFontsPropertySection.java:85)
	at org.eclipse.gmf.runtime.diagram.ui.properties.sections.appearance.ShapeColorsAndFontsPropertySection$1.widgetSelected(ShapeColorsAndFontsPropertySection.java:42)

Obviously the use case I mention does not happen regularly, but if an user uses the palette regularly for several hours he will encounter it (that's how the bug was found).