UE4 Slow UI

Its quite hard to explain with a screenshot as the lag happens to any project i open. but i have attached it along with annotations. its just when i click something i.e. when i search for a static mesh in content browser, or change an attribute in details panel. the blue area is where performance is good there is no lags when i move about in the viewport. but when i move my mouse over the red areas the performance is slow its not very quick in selecting.

Thanks,
Iby