[HD2 Windows Mobile 6.5 ROM Development] Z80-Man:
Hello,

I did some researches and experiments, as scrolling speed bothered me too.

It's important to note that the only problematic one is about the thumb slider that replaces the classical WM slider and arrows scrollbars, as it has never been a concern when the program you're using allows direct full screen finger scrolling.

The main concerns are on the top part of the registry editor (strangely enough, you can't full screen scroll the upper (keys tree) part, while you can on the lower (values) part), and file browers such as Total Commander, when you want to quickly reach files.

Actually, the more files (or registry keys on an expanded tree) you have to parse, the less precise it becomes. It acts as it moved by a percentage, whatever the number of lines to scroll (it probably works like that, BTW).

It's nice when you have few lines to browse through (but in the case of TC, you actually don't need to use it, then, since vertical and horizontal since finger scrolling work as well), but becomes very rough when you have a huge amount of files, such as browsing the \Windows folder (where you badly need to move fast). And of course, it's your only way to browse the registry, so browsing HKLM is a pain in the ass, and I'm even not talking about browsing HKCR ! :p

As far as I could figure out, it's an HTC addition (and replacement) to the classical WM scrollbars system. It's actually absent from the HD, because on the latter, you can use a stylus to operate the tiny arrows buttons, so it kept the plain classical WM system... But on the HD2, it's been replaced by this thumb slider that pops out as soon as your finger approaches a scrollbar.

The registry keys containing information controlling the scrolling are the following :

[HKEY_LOCAL_MACHINE\Software\HTC\SmartTouch]

and

[HKEY_LOCAL_MACHINE\Software\HTC\TouchGL]

The second one should probably be the one to look at. Note that it also controls the pinch to zoom behavior.

I think the first one contains a list of applications that use the new scrollbar system with options I couldn't really understand yet, while the second one contains a list of applications that use the pinch to zoom system (in the subkey [HKEY_LOCAL_MACHINE\Software\HTC\TouchGL\Pinch]), and can be used by the Zoomer add-on program (search XDA for it) if your application doesn't natively manage the pinch to zoom system, such as Opera 10 (it actually doesn't manage progressive zooming at all, that's why PTZ doesn't work natively. It's also the reaon why I went back to Opera 9.7 !)

[HKEY_LOCAL_MACHINE\Software\HTC\TouchGL] contains general information and control values such as :

"ScrollBarExpandDown"=dword:0000000D

"ScrollBarExpandLeft"=dword:00000014

"ScrollBarExpandRight"=dword:0000000D

"SelectIndHeight"=dword:00000064

"StayTimePerAnimation"=dword:0000000C

"ThumbExpandHeight"=dword:0000001E

"ThumbMin"=dword:0000001A

"TimeoutForAPPRespond"=dword:00000BB8

"TouchArrowDiff"=dword:00000007

"TouchDrawPeriod"=dword:00000014

"TouchDrawPri"=dword:0000006D

"TouchGLDebug"=dword:00000000

"VelocityFactor"=dword:00000005

You should play with some of these values and see what changes they bring. :)