I feel like this has been mentioned in the past but I can’t find the topic.
When I select a block and use command BlockEdit it sometimes takes 45-60 seconds to happen. Double-click on block has same symptoms.
This seems to start happening at some indefinite point as my project file grows in size. Meaning, with a new file and new blocks: no problem. BlockEdit launches immediately. After a year or two of project development, somewhere along the way all BlockEdits take a minute (or more) to start.
Purging unused blocks doesn’t seem to do any good. If I export the blocks to a new file they work fine (blockedit is fast in the new file).
The current file saved small is 124Mb. I dunno if attaching it to this post is a good idea? I can share a dropbox link or upload to support (via: http://www.rhino3d.com/upload), whatever you prefer.