dcl-Control-SetVisible / NIL value not allowed

[Peter2]

At the moment I'm rather confused.

I have a "chain" of modal forms, the last shows a lot of pictures and has two buttons "Show part 1" and "Show part 2. The first image has also a click-event.

I call the form, it is displayed, the test-onclick-event on first image is triggered. Then I press the button "Show part 2" and this routine is called:

Code Select Expand

(defun c:Einstellung/dlg_schraff/btn_teil1#OnClicked (/ zaehler)
    (alert "hallo1")
    (dcl-Control-SetVisible rbi_siaEinstellung/dlg_schraff/PictureBox1 t)
    (dcl-Control-SetVisible rbi_siaEinstellung/dlg_schraff/PictureBox2 t)
    (dcl-Control-SetVisible rbi_siaEinstellung/dlg_schraff/PictureBox3 t)
    (dcl-Control-SetVisible rbi_siaEinstellung/dlg_schraff/PictureBox4 nil)
    (dcl-Control-SetVisible rbi_siaEinstellung/dlg_schraff/PictureBox5 nil)
)
The code starts, I get the alert, and then I get

Code Select Expand

Error: NIL value not allowed
Function: dcl-control-Setvisible
Argument: 2

Any hints .. ??

[Peter2]

 >:( >:( >:( >:( >:( >:(

"Solved": Some refreshing / reloading / error offering problem. Total restart - now it works.