Major
#28227
Dialogs get +100 size for the core theme, regardless of the unit of size (px, %)
DialogWindowControl.writeRenderingCommand(DisplayContext, Appendable) contains code that always adds DialogWindowControl.HEIGHT_ENLARGER ("100") to the size of the dialog. The comment reads:
Additional height added to ensure dialog windows are displayed correctly in the core theme.
Unfortunately, this ignores the fact that the size can be specified not only in pixels but also as a percentage. As a result, this change means that dialogs with a percentage size always take up 100% more space than configured. They are therefore always displayed maximized. "Only" 50 is added to the width.
Due to this error, it is currently not possible to configure dialogs with a percentage size.
Test
Inspect the dialogs in the application. Create a dialog with percentage dimension values and check whether the addition no longer occurs.