Bug - edit block properties very slow


I have a large linked block (700MB) in my file (scene like this http://www.manager-magazin.de/images/image-527208-mmo_panoV9-bnst-527208.jpg) and I try to change the link to an other version of the file. If I double click on the entry of the block manager than I need to wait a long time until the properties window is opened. Could be nice if this delay could be avoided.