When a unit or building is selected, there is an invisible, unclickable area of the screen from where the name of the unit portion fades out to the end of the unit box. Clicking there does not allow you to select units or click and drag because it is behind an invisible UI box.
It makes it very difficult to know where to click in that area of the UI. Often when I am selecting my starting villagers I have to click around several times which is frustrating.