Description Mike Marchand 2019-01-08 13:26:32 EST

Created attachment 277106 [details]
Screenshot of Table with wrong sort column background color.

This issue was discovered while working on a custom Dark theme for our product.

The issue arises when a Tree/Table and it's backgroundControl (from findBackgroundControl()) have the same background.

From CSSSWTColorHelper.java
/** Helper function to avoid setting colors unnecessarily */
public static void setBackground(Control control, Color newColor) {
	if (!equals(control.getBackground(), newColor)) {
		control.setBackground(newColor);
	}
}

If the newColor is the same color as the Tree's backgroundControl then we will never call control.setBackground() which will leave Control.background = -1.

Later when a Tree goes to render and it calls getSortColumnPixel(), that function does not look at the backgroundControl, it calls getBackgroundPixel() which looks directly at Control.background.  Since Control.background is -1, it will return OS.GetSysColor(OS.COLOR_WINDOW) which in my case was white.

I believe(am not certain) the fix is to fix getBackgroundPixel so that it looks at the backgroundControl's color.

The workaround was to force Trees and Tables to be a different color then other backgrounds in CSS.