I was contacted by a very helpful person who tried the Linkage program and had some very good suggestions. I fixed a few bugs and then implemented a few of the less complicated features that we discussed.
Fixed a problem where I had added , and . shortcut keys for stepping the simulation and caused the . and , to not work in the coordinate/distance text box in the ribbon. That text box allows the distance to be set between a pair of connectors or allows the x,y position of a single connector to be changed.
Fixed a problem where the inches/millimeter information was not set correctly for the document when reading in a file. I think that it was just showing dimensions as millimeters even if the mechanism was saved with inches selected. Switching back and forth from inches to millimeters to inches fixed the problem but the code now works correctly.
Added the ability to set a position for a selected connector using the Connector Properties dialog box. There are now two edit controls in the box for setting the x and y coordinates.
Added an Auto Join feature. If the Object Snap is enabled and the Auto Join is enabled then dropping a single connector onto a single other connector will cause them to be joined. This is a permanent join since dragging the new connector doesn’t unjoin or Split them. Only the Split operation can do that after they are joined.