My problem is: the "Toolbox" is not shown. I tried my own project and the original traffic example. After that I restarted my Windows an KEIL. If I try to start the Toolbox the Windows title bar changes from blue to light blue. Of course I have closed all other programs, minimised all windows, disabled the second monitor.
Any ideas what's going wrong?
Not strange. You can place the default location of windows within the visible coordinate system of the desktop.
If you later decreases the vertical or horisontal dimension, you can get programs - or document windows - that opens at their saved coordinates - now outside the visible space of your changed desktop.
When implementing GUI applications that stores window coordinate information, it is strongly recommended to always compare any loaded configuration with the current desktop size, to make sure that the above problem does not happen.