With the Subject option selected, a Standard View skin incorrectly draws the expanded Scrollbar VerticalHandle (same for horizontal handle). It appears the handle's endpoint sub-images are stretched in one direction, but not the other, resulting in a distorted handle image during enlarged mouseover and during an enlarged scrollbar drag. Many enlarged scrollbars have always looked goofy to me, and I think this is partly to blame.
Example: I define the handle to be a simple rounded rectangle with (corner radius) = (rectangle narrow dimension) / 2, thereby giving smooth "half round" ends to the handle (see attachment, but I've seen the same issue with other handle images and other Standard View skins). With the Subject option deselected everything looks good, nicely rounded as expected. With the Subject option selected, the ends appear squashed, as if stretched in one direction but not the other.
I use the following code in the <SCROLLBARS> section of the skin's main.xml file:
<Entry Name="VerticalHandle" Bitmap="Scrollbar_VerticalHandle.png" NumberImages="3" Margins="0,5,0,5" Scale="1" DrawMode="REGION_E_VSTRETCH"/>
<Entry Name="VerticalBackground" Bitmap="Scrollbar_VerticalBackground.png" NumberImages="1" Margins="0,5,0,5" Scale="1" />
<Entry Name="VerticalUpArrow" Bitmap="Scrollbar_VerticalUpArrow.png" NumberImages="3" Margins="0,0,0,0" Scale="1" />
<Entry Name="VerticalDownArrow" Bitmap="Scrollbar_VerticalDownArrow.png" NumberImages="3" Margins="0,0,0,0" Scale="1" />
Seems like a bug to me. I messed around with several other DrawMode values and did not find anything that changed the described behavior. In any case, it cost me several frustrating hours to unravel this story while modifying a skin with the option selected.
General Comments re Subject option: It's 100% an optical illusion, and I've decided never to use it (at least as currently implemented). This option in no way affects the actual operation of selecting the scrollbar and scrolling: (1) It does not make it easier to initially "hit" the scrollbar (initial target area is not enlarged) (2) During scrolling, the LMB down mouse can be dragged anywhere on the screen while continuing to scroll (a good thing), irrespective of this option setting. (3) It has the annoying side affect of temporarily pushing all the Control Panel thumbnails to the left.
Note: MC must be re-launched for a change in the Subject option to take affect.
Win11 Pro (64-bit) | Win10 Pro/Home (64-bit) | MC 32.0.49 (in beta)