>Take aslo look at Developer-defined Btn(s) on Standard VFP toolbar Thread #611029.

This works. I've had problems with the .prg being locked during testing, so I've given it a temp name and made it vanish with the toolbar... in the end. Here's my modification of your and Zlatin's code:

*[2002.10.27 14:44:13] dragan -  if we used a little prg to restart this, kill it
	If Not Empty(This.ccreator) And File(This.ccreator)
		Erase (Forceext(This.ccreator,"*"))
	Endif
* .lAllowClose is set from exit button only
If This.lallowclose
	_Screen.otestbar=.Null.
Else
	Local lcSetSafety, lcExePath, lcPRG

	lcPRG = ForcePath(Forceext([tmp_]+Sys(2015), "prg"), JustPath(this.ClassLibrary))

	If _Screen.ReleaseType != 2 Then
		Local lcCommand, lcSetSafety, lcPrg
TEXT TEXTMERGE to lcCommand noshow
	_SCREEN.AddProperty('<<This.Name>>', NEWOBJECT('<<This.Class>>', '<<This.ClassLibrary>>'))
	_screen.<<this.Name>>.cCreator="<<lcPrg>>"
	ON KEY LABEL RIGHTMOUSE
ENDTEXT
		lcSetSafety = Set([SAFETY])
		Set Safety Off
		Strtofile(lcCommand, lcPRG)
		Set Safety &lcSetSafety
		On Key Label RIGHTMOUSE Do &lcPRG
*[2002.10.27 15:06:37] dragan -  open it just in case ctrl+f2 is not available
		Activate Window command
		KEYBOARD '{CTRL+F2}{RIGHTMOUSE}' CLEAR
	Endif
	Return .F.
Endif

Works great so far - thanks for nudging me in the right direction.