Fixing possible container crash and fixed size window sizing
Just a few small fixes that improve stability of rapidly changing containers and fixes a sizing issue for some fixed size windows.
Fixed
- SetTheme() is not fully effective for widget.Form (#2810)
- FolderOpenDialog SetDismissText is ineffective (#2830)
- window.Resize() does not work if SetFixedSize(true) is set after (#2819)
- Container.Remove() race causes crash (#2826, #2775, #2481)
- FixedSize Window improperly sized if contains image with ImageFillOriginal (#2800)