Yes, it helped. It is a reasonable workaround. In fact , I've given a wrong snippet of the code there is no need locking while bar is being dragged , moreover it prevents seeing it dragged.

in mousedown event

application.autoyield = .T.
DO WHILE MDOWN()
thisform.activex.visible = .f.
lnCurPos = MCOL() * lnAvgCharWidth
this.parent.Move(MAX(lnMinPos, MIN(lnCurPos, lnMaxPos)))
ENDDO
thisform.ftxfast.activex = .t.
application.autoyield = .F.

Class Browser/Component Gallery seems to be written in Foxpro ( is source available BTW ? ) and similar workaround seems to be used then.

>>Unfortunately ActiveX remains opaque and resizing possible without limitation only in one direction. In the direction of ActiveX it only possible in small increments ( till part of the bar is visible ).
>>
>> <--- okay
>> editbox | activex rectangle
>>
>> ---> problem
>> editbox | activex rectangle
>>
>>Any ideas ?
>
>How about making the AX invisible while the splitter is dragged? It shouldn't hurt as you already have the lockscreen set. BTW, thisform.lockscreen, or _screen.lockscreen? IMO, you could try one at a time, and see if it changes the behavior.