When aero is enabled, GUI scrolling causes system to lag

[drapdv]

I have a GUI with a parent window that has a menu and shortcut buttons at the top, and a child window which displays a list which is scrolled vertically.

When the list is relatively small, like no more than 100 or so lines then it scrolls fine.  As the list gets larger, scrolling begins to slow, and if you start mixing up the scroll method (mousewheel, left-clicking the scrollbar box, etc) then it begins to hang.  When it hangs, dwm.exe CPU usage maxes out, and I can't even switch to another window.  Each line in the list is 1000px wide X 30px tall, and the lines alternate between a gray background and a white background, in case that matters.

When a non-Aero theme is active, everything works fine.  So, I could disable DWM every time someone fires it up, but changing a client's color scheme is not ideal.

I tried to utilize _WinAPI_DwmSetWindowAttribute($oGui_Parent,  $DWMWA_NCRENDERING_POLICY, $DWMNCRP_DISABLED), and although it succeeds in disabling DWM for that window, it doesn't seem to make any difference as far as the scrolling lag is concerned.

The code is several thousand lines long and contains proprietary information, so I'm trying to avoid posting that, but these are the lines which are creating the GUIs.  Is there anything that anyone can think of off the top of their heads, or is there anything jumping out at you from this snippet of code?  Any help is appreciated!

$oGui_Parent = GUICreate("Data Viewer", 700, 500, Default, Default, BitOR($WS_CAPTION, $WS_MINIMIZEBOX, $WS_POPUPWINDOW))
    WinSetTrans($oGui_Parent, "", 255)
    _WinAPI_DwmSetWindowAttribute($oGui_Parent,  $DWMWA_NCRENDERING_POLICY, $DWMNCRP_DISABLED)
    GUISetFont(9, 500, 0, "Calibri")
    GUISetBkColor(0xFFFFFF)
    
    $oGui_Child = GUICreate("", 700, 400, 0, 100, $WS_POPUP, $WS_EX_MDICHILD, $oGui_Parent)
    WinSetTrans($oGui_Child, "", 255)
    _WinAPI_DwmSetWindowAttribute($oGui_Child,  $DWMWA_NCRENDERING_POLICY, $DWMNCRP_DISABLED)
    GUISetFont(9, 500, 0, "Calibri")
    GUISetBkColor(0xFFFFFF)

 

Edited February 24, 2017 by drapdv