.xml not working. Not sure which one.

[Psycho]

The .xml that control the message box that pops up when you hail a guard trying to find a specific NPC and you need to input the NPC's name. Right now I cannot do this since the text box appears completely black and I cannot select it to input any text. The problem is I don't know what .xml file controls this aspect of the UI. I do not want to revert all of the my custom UI to fix one problem, please if you know which .xml this is, please reply. Thanks.

Here is a screenshot of the problematic window.