Zmodeler 3 'Freezes' when selecting Face/Edge/Vertex Mode

[Double Doppler]

Hi, as title suggests. Running latest version of Zmodeler3. Working license. Program was running fine last night with the same model. Now, whenever I enter Edge/Vertex/Face mode (anything other than 'Object' mode) it freezes, regardless of whether an object is selected or not. Help would be appreciated - was going to post in the general discussion but there was no option to create a new topic.

Edit: imported mesh into a new z3d file, works now it seems - but any idea why this happened in the first place and how to avoid in the future?

[Oleg]

when something is selected, materials browser "scene selection" is updated, and properties window checks for properties on selection. There might have been an issue with the scene that some of these tasks failed/hanged. If you have an old saved .z3d file that still suffers this issue, you can send it to me and specify the problematic object that causes app to freeze, so I can check it.