A lot of the time when im fighting and i open and close a menu the screen stays gray can i cant click on anything or do anything only fix is reloading the game :(
Are you sure? Try unequipping all items and check if your priests, for example, have exactly 1.00 mana regeneration per second or more (they should get +0.1 for each priest tent, and +0.01 for each well).
Still happening?