Hey there, I think I may have found a bug in Construct 2 or Firefox or something like that. I have two screenshots below, one shows before the glitch happens the other afterward. In case you are wondering the red background is a tiled background, the silvery text is a text object, the white boxes are lists, and the orange box is a text area.
<img src="https://dl.dropboxusercontent.com/u/22535351/Glitch1.PNG" border="0" />
<img src="https://dl.dropboxusercontent.com/u/22535351/Glitch2.PNG" border="0" />