6270: Attempting to accidentally open Book Manager raises a Unhandled exception


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps40@20971 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
6273: Detaching Gramplet in Sidebar/Bottombar views are not using full area


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps40@20973 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
Fix of divison issue. There might be more of them.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps40@20976 4ae1f11a-8b86-4847-b8af-ab372f36d1fd