delay menu loading

Hi to everybody!
i have a problem during the menu load.
In my project i have an access login.
After the test of the password, i assign apps permission for create the menu.
The problem is when the menu appear: in the first step the menu is open and without icons; after 1 second it becames correct.
How can i delete the first step of the menu loading?
I tried to delete icons but it’s the same

Grazie a tutti