In the TAdvPenWidthSelector control, it seems like the images used in the dropdown are not the one displayed after selection.
For example, to make it simple, I reduced the default Selector Items to just three:
Item 0: ImageIndex = 0
Item 1: ImageIndex = 3
Item 2: ImageIndex = 5
When the drop down is shown, the images go from: thin, medium, thick (relatively speaking). If I pick the first one, the selector then shows an image that is thicker than the one I picked in the dropdown. It looks like it is showing the medium thickness instead. Likewise if I select the medium one, the result show the thick line. If I pick the thick line, it shows an even thicker line that isn't even in the dropdown images.
Almost as if the image drawn in the selector uses a higher image index than the one used for the drop down images.
TAdvPenWidthSelector 1.4.0.0
Delphi Rio 10.2.1