WM_DRAWITEM of SysTabControl32 is overpainted?

Question

I have to restyle our SysTabControl32, so I'm trying to use TCS_OWNERDRAWFIXED and WM_DRAWITEM. Everything works well BUT it seems that the Tabs are still overpainted by the system.

Unfortunately the code is in Visual Objects which makes things more complicated. I already tried a lot of things during the last hours and for the time being I'm clueless. Maybe some of you guys can help or give ma a hint.

Here are some Pictures:

"Naked" Tabcontrol with TCS_OWNERDRAWFIXED. No code at WM_DRAWITEM.

You will notice that the tabs are not filled, but the 3D-Style is painted. And this is my main problem, because as long as I know this shouldn't happen.

Ownerdrawn Tabs with Text and Background Color (ugly but useful in order to see the Problem)

The same TabControl but with TCS_FLATBUTTONS and TCS_EX_FLATSEPARATORS set. Still the problem with the grey background.

As you know WM_DRAWITEM will be catched in the parent window. I also tried to overwrite or ignore WM_PAINT in the TabControl itself. But it don't help.

Also I played with WM_ERASEBKGND, but I'm stuck at this point.

At all pages starting from codeplex to codeguru or even vbAccelerator it should work. Should :) Don't know if it's visual objects, but API are API and this is still a standard control.

WM_DRAWITEM contains this code, which seems okay. item is DRAWITEMSTRUCT.

hdc := item.hdc
tabIndex := item.itemID
lSelected := (item.itemState == ODS_SELECTED)

wBrush := CreateSolidBrush(RGB(128,128,255))
FillRect(hdc, @item.rcItem, wBrush)
DeleteObject(wBrush)

SetBkMode(hdc,TRANSPARENT)
tTI := MemAlloc(_SizeOf(_winTC_ITEM))
tTI.cchTextMax := 255
tTI.pszText := String2Psz(Buffer(255))
tTI.mask := TCIF_TEXT
lr := SendMessage(item.hwndItem, TCM_GETITEM, item.itemID, LONG(_CAST, tTI))
if (lr != 0)
     if (lSelected)
         SetTextColor(hdc,RGB(255,0,0))
     ELSE
         SetTextColor(hdc,RGB(0,0,255))
     ENDIF
     DrawText(hdc,tTI.pszText,-1,@item.rcItem, _OR(DT_SINGLELINE, DT_VCENTER, DT_CENTER))
ENDIF
MemFree(tTI)

Answer 1

This is my trick to custom draw SysTabControl32

RECT defaultRect = lpDrawItemStruct->rcItem;
//
// Begin of WM_DRAWITEM, we clear the clip rect
SelectClipRgn(lpDrawItemStruct->hDC, NULL);
..
..
..
// End of WM_DRAWITEM, we create a clip rect to disable default system border
ExcludeClipRect(lpDrawItemStruct->hDC, 
        defaultRect.left - 3,
        defaultRect.top - 2,
        defaultRect.right + 3,
        defaultRect.bottom + 2);

Reference: https://github.com/pladaria/emule/blob/master/srchybrid/ClosableTabCtrl.cpp