I do some tests with ZWCAD ( I have installed previous version of ZWCAD 2014 + till opendcl 184.108.40.206 :-) )
I found a problems with BlockView control (dcl-BlockView-DisplayDwg).
Method dcl-BlockView-DisplayDwg shows block after loading, then i try to insert block into drawing and ZWCAD crashes.
After secound loading of file doesn't show proper preview and then ZWCAD hangs. I can close it only by ending process. The problem is in Demo (ViewDWG) sample.
WIN 7 x64