If strict mode is enabled, you can't save a news item without putting a number in the "Appears in position" field. The operation fails silently and this error appears in the log:
DBD::mysql::st execute failed: Incorrect integer value: '' for column 'number' at row 1 [for Statement "UPDATE opac_news SET number = ?,expirationdate = ?,lang = ?,timestamp = ?,title = ?,branchcode = ?,content = ? WHERE idnew = ?;" with ParamValues: 0="", ... ] at /kohadevbox/koha/C4/NewsChannels.pm line 106.
Will certainly be fixed by bug 22544
*** This bug has been marked as a duplicate of bug 23430 ***