Yes its very curious.
I just tested it on one PC - the Message WM_WPTOOLSUPDATE is sent and received,
I set a variable to now in the procedure TWPCustomRtfEdit.WMWPTOOLSUPDATE ... and checked it.. everty time i enter a char, this variable has been updated, but i see no text on the screen - if i execute ReformatAll manually than i see the text!
I allray changed the Value of the WM_WPTOOLSUPDATE.
And yes the component is on a PAgeControl, but an other form, has the same effect - and this window have no PageControl on it.
I have a DebugText of same vars in this procedure ... maybe you can say something ....
fNowDestroy: 0 wParam: 5 lParam: 0, InWaitForPAintEditor: 0 IsDynamic: 0 Locked: 0