If you click on maximize icon in cke editor and try to open LinkIt or Add media (anything that uses jquery ui-dialog), then z-index of the dialog will be lower than ckeditors full screen window and popup can't be seen.
CKeditor full screen z-index is 9999. There's a a parameter called zIndex in ui-dialog, that makes the fix quite simple.
Patch in next post.
FAILED: [[SimpleTest]]: [MySQL] Unable to apply patch media-ui-popup-hidden-in-full-screen-1779984-1.patch. Unable to apply patch. See the log in the details link for more information. View