Different scroll box sizes with dark mode on and off

[DrShark]

29.10.19 Added: Dark mode: Partial support for dark scrollbars in listboxes on older Windows versions (only when scrolling with the keyboard) (32/64)

Here on Vista 32-bit, when a list of many files is opened, there's a visible difference of scroll box (aka slider aka thumb) size with dark mode off and on: with dark mode enabled it is ~3x larger (takes more place in a scroll bar). If it is intentional (because this way it covers a real smaller scroll box drawn by Windows and some space near it,) then topic may be moved to "TC Behaviour which will not be changed" subforum.

[Usher]

Slider and other widgets may be larger or smaller because of thick borders used in Windows style. Can you see different size of the list length? In Windows XP the list in dark mode is about half a line longer, in Vista it may be difference by a line or more in full screen. You can also change windows theme to classic (Windows 2000 like) and report the difference for that case.

Dark mode support is really partial - when you scroll list with mouse, the scrollbar blinks (flickers) with color from Windows style. When you scroll further and reach the bottom of the list, both scrollbar and slider may get colors from Windows style.

[DrShark]

Can you see different size of the list length? In Windows XP the list in dark mode is about half a line longer, in Vista it may be difference by a line or more in full screen. You can also change windows theme to classic (Windows 2000 like) and report the difference for that case.

Theme is already classic, and file list lengths with dark mode on and off seem to be the same: screenshot

[Usher]

I don't know which size is more accurate, but I think that some calculations may be still made for Aero. Read this article:
https://www.reviversoft.com/blog/2012/03/disable-the-aero-interface/?lang=en
Note that you should also disable desktop composition for separate programs. You can also check widget sizes after stopping of composition service and with Aero turned on. Use folder with shorter list to observe whether the slider change is proportional to the list length or constant - it may help to find possible bug in TC.

[ghisler(Author)]

Thanks for the screenshot. The problem is the minimum scrollbar button size when there are a LOT of entries in the list. On Windows 7 and 10, the minimum size is a square button - at least when themes are enabled. That's what I'm using in dark mode too. Without themes, it seems to be a much smaller button. Unfortunately I have no idea which is the minimum height for various screen densities - any ideas?

[DrShark]

05.11.19 Fixed: Dark mode, File lists: thumb box was too high with classic theme when there were a lot of items in the list (32/64)

In TC 9.50 beta 4 scroll box sizes with dark mode on and off are the same now, at least on my configuration, thanks for the fix.

[ghisler(Author)]

According to my investigation, Windows without theme uses an 8 pixel high scroll box at 100% scale (96dpi), which is scaled linearly with the scale factor (e.g. 150% scale -> 12 pixels).