7480fab1____an_overlay_plugin_for_Ender__Description
[Property] position [Default Value] "absolute" [Description] 
You can use absolute or fixed as a value. With absolute, the overlay will stay at the given position. With fixed it will stay in place even when you scroll. If you choose fixed, make sure to your overlay fit in the viewport, because at lower resolutions it can be a problem.
Ender-overlay - an overlay plugin for Ender
Description