The problem is visible on KDE desktop because calling xdg-open with wrong argument will show a message box with the error. If you test on Ubuntu(Gnome) please launch theIDE from terminal and then see the errors while accessing Help from theIDE.
Quote:
/usr/bin/xdg-open
Error showing url: Error stating file '/home/can/topic:/ide/app/index-us': No such file or directory