The history of the web pages visited by a user is listed in a TreeView. When the mouse is moved over each node in the TreeView, a tooltip appears with the title & the URL of the web page on which the mouse currently rests. Since the TreeView doesn't inherently support tooltips, I am using a Frame with a Label control to render the tooltips (the Frame encompasses the Label).
What I find is if the mouse is moved over the TreeView at a brisk pace, then the tooltips (i.e. the Frame with the Label) leaves its trailings on the web page. Please have a look at the image attached to get a better idea of what I am trying to say.
Note the thick dark blue area in the image. The dark blue area is actually the trailings left by the tooltips that were generated when the mouse was moved down from the upper edge of the entire dark blue area till the tooltip (towards the bottom with the light yellow background).
Any idea how do I avoid that dark blue area which is the result of the tooltips when the mouse is moved over the TreeView at a brisk pace?