Issues with screen layout within a call

Hello

we have an issue with several users of the Officer Portal. When they go into a call, the divider between the navigation options to the left of the view (Favorites/Main Nav) and the call details is pulled across to the right, obscuring the call details. If this divider is pulled across to the left so that the Call details are visible again, and then you exit the call, this view isn't cached as the default. Once you open a call again he divider is across to the left hand side again.

Is there a way to resolve or reset this so that both the navigation bar and call details are visible on the screen and this si the default view. Where are the defaults cached?

Many thanks