Thank you Martina
there is a small typo in your code

with thisform
For m.lii=.ControlCount TO 1 STEP -1
     m.loObj=.Controls(m.lii)
    =IIf(Lower(loObj.Class)=="ycnt",.RemoveObject(loObj.Name),.T.)
Next
endwith

When use the [for i=1 to .controlcount]......i put a structure try/catch/endtry for avoiding error (there is always error) !
you used [for i=.controlcount to 1 step -1] maybe have a real signification ? Is vfp stores containers by the last created ? there is a memory lost when using the other syntaxes?