Anything in the info and verb panel is always on the top layer.
The browser and text act correctly.
Numbered Steps to Reproduce Problem:
Open game in Chrome or IE.
Expand verb/info area to overlap middle.
Open any dialog
Expected Results:
Layering would have all dialogs above the text.
Actual Results:

Workarounds:
Changing z-index of .byond_info_tab.selected and .byond_info_contents appears to have fixed it, without any negative side effects.