Popup becomes visible: In a screen with a grid control I have added a pushbutton that reads all grid rows and then reads additional data for each row. I use the Windows clipboard in order to get all grid rows:

Enter "==%PC"

Screen SAPLSPO5.0110

  Set R[In the clipboard]   "X"

  Enter
...

This works fine, but the SAP popup where you choose the file type / clipboard becomes visible for a short time. How can I avoid this effect?

In GuiXT version 2015 Q2 1 and above the popup will no longer become visible.
As a workaround you can use "Disable controls" for the popup screen:

Enter "==%PC"

 Screen SAPLSPO5.0110

  Disable Controls

  Set R[In the clipboard]   "X"

  Enter

....