Try commenting out the definition of "second_panel" as a test.

Also what version of 3DGS are you using?
If you are using A7.63 or higher, you should be using the
SHOW flag on the panels, not VISIBLE as it was changed to SHOW in A7.63

[EDIT] Hehehe, good point Joozey. I didnt notice that the mouse never
gets turned on cause the mouse action is never actually called...