When all the categories are collapsed, last_post is not properly set leading to undefined index errors - thanks Ruth for the original report
When all the categories are collapsed, last_post is not properly set leading to undefined index errors - thanks Ruth for the original report

Signed-off-by: emanuele <ac2faa8b943b3fcadaf05ed2541f4eebde440ed7@gmail.com>

joshuaadickerson/Elkarte2,elkarte/Elkarte,emanuele45/Dialogo,Ant59/Elkarte,nwsw/Elkarte,StealthWombat/How-to-fork-an-Elk,StealthWombat/How-to-fork-an-Elk,elkarte/Elkarte,wizardaf/Elkarte,Ant59/Elkarte,nwsw/Elkarte,elkarte/Elkarte,wizardaf/Elkarte,joshuaadickerson/Elkarte2,Spuds/Elkarte,joshuaadickerson/Elkarte2,wizardaf/Elkarte,emanuele45/Dialogo,interlab/Elkarte,emanuele45/Dialogo,StealthWombat/How-to-fork-an-Elk,wizardaf/Elkarte,interlab/Elkarte,Spuds/Elkarte,StealthWombat/How-to-fork-an-Elk,nwsw/Elkarte,joshuaadickerson/Elkarte2,Ant59/Elkarte,Spuds/Elkarte,interlab/Elkarte