OK, my last version.
I changed the Block Preview to a Drawing Preview to speed things up. I added a Preview button that brings up a separate modeless form for panning and zooming. The whole app is much faster now. If there are any changes in the future I've included the command "BlockManagerVer" which returns the version number.
I'll be working on an alternative version using drawings as containers for my own use. I'll definitely share when I get a working copy done.
My intention was to provide a real world example of how easy and robust OpenDCL is. I hope this example will help with anyones future development.
New version up on first post.