GLUI_Scrollbar problem with GLUT keyfunction

Dear all,
I am facing a problem by adding some GLUI sidebars including GLUI_Scrollbar everything is working fine the bar is added and I can drag the slider by mouse and get the value with the range limit.
BUTTTT , the weird thing which I still did not understand it yet is that whenever I use the slider using mouse the functionality of GLUT keyboard stops the interaction without reporting any kind of opengl error or at least the common opengl errors I used unless I should use some glui getting errors that I am not aware of :{

Any kind of help or leading to the start point where can I find the problem are appreciated

I have to say not normal key but function keys as F1, …,F12
and I have just tested the normal keys function a,…,z with the same task that is given to function keys, so they are working well…

Even if my problem is solved by replacing function key by normal keys, I still want to understand if anyone knows what the issue with function keys and how could be solved…