Hi, Markus -
PB uses the standard Windows controls (except in DataWindows, where they are emulated by PB) unless, as Armeen mentioned, you uses PB themes or a third-party alternative set of visual controls such as PBUltimateSuite. Windows uses several of its system color settings to render "3D" objects such as command buttons, scrollbar thumbs, scrollbar background, etc.
Technically, yes, the colors used to render the standard TrackBar controls CAN be changed, but only by altering the Windows system color settings for 3D objects via the Windows SetSysColor API function. However, doing so changes the color for all types of 3D objects (not just scroll bars) across all applications that utilize the standard Windows Trackbar controls. This is not a very practical solution and I therefore do NOT suggest that you do this.
This is probably a major reason the use of "skins", themes, and the like have grown in popularity.
Regards, John
I might even try enabling more parts of Theme, since most of the problems with enabling themes in our application are centered around DW design.