When trying to select, in this instance, a static mesh, as soon as the mouse is over my selection there is a popup that blocks my ability to make a selection as clicking only closes the drop down menu and the informational popup.
[Video Example Here][1]
This also happened in 4.14 and is not specific to this project. It only causes issues if the drop down is in the right side of the screen. If it is on the left I can easily select a static mesh, or material, or what ever I am trying to select.
[1]: - YouTube