Can't edit a custom model/tool

[CelesteWalz]

I built a model using model builder with help from this group (see this thread: https://community.esri.com/message/700561-re-repetitive-task-model-builder-or-python) but now I have a new problem: I can't open the model to edit the input and the output. I would like to get it to open in the model workbench (with the lovely flowcharts) but I get a blank window when I right-click--> edit or right click--> open.

I get the above when I open model builder first and then drag the tool into the window.

I'd really like to use my tool again if possible.  The old thread has some things I've tried, but i'm hoping for some more input.

[AbdullahAnter]

Did you try to fix zoom using Full Extent button in the following picture, before drag the model?

[CelesteWalz · Accepted solution]

Full extent didn't work, but Chris Donohue (from previous thread) suggested the window might be hiding. I had a good close look around the margins of my monitors and found the tiniest sliver of frame in the corner that I was able to expand and get the window out. *whew*.