The little plus in the sheet tab bar needs to be protected when we are in an ScAnyRefDlg. Even worse it makes it possible that the table switches when the IsTableLocked returns true so allowing the user to insert references to other tables.
Needs to be fixed for 3-7 to prevent crashes in the cond format code.
Markus Mohrhard committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=da7edb8bd74eb3c42a4585254e5bb329905b56c8 in ScAnyRefDlg + table locked, don't allow creating new sheets,fdo#55709 The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.