WC List remains on the top left of screen after selecting WC Structure in IE11
1. Create 12 web content structures. Content > Web Content > Three dots top right > Structures
2. Add Web Content Display portlet to the Welcome page.
3. Click the Plus on the portlet and make sure the list has a scroll bar.
4. Select a structure.
The list will remain on the upper left corner of the screen blocking the new content window.
The list will disappear allowing user to edit the new content window.
You may need to scroll the list to the bottom then select your structure for the bug to happen.
Reproducible: Master, 7.0.x