Well I know that the canvas is in edit mode as anytime I try to click anything I end up grabbing something and resizing it instead, and toggling edit mode on and off in the edit menu makes it behave as expected. The thing with having no indication of currently being in edit mode was only happening when I would first open the patch, and as mentioned I could tell that it was in fact on because whenever I would try to click on anything in the PD window with the mouse the cursor would instead select or start resizing whatever was beneath it.
Thinking about it now I figure it must have something to do with donecanvasdialog, would that make sense? I'm not using any gui plugins and no externals are interacting with the gui, but I am using a number of structs. I'll check that in a couple of hours when I'm back at home.