I have now the same problem with release 80.
In my case this what happens:
- Insert new object
- Tiled background
- cross mouse pointer to insert the object
- after clicked, the "Edit image: Tiled background" opens
- I do nothing, I simply click the [X] close button to exit, but the window stays opened and Construct is blocked.
- If I repeat this procedure and I try to add an image, the image appears in the edit window, but the window can't be closed and sometimes Construct crashes.