Does this happen on multiple projects, new projects or just one current project you have? Because, there is a chance your project might have silently corrupted.
If you think this is the case, try this:
- Chrome > F12 > Application (tab) > Clear site data (button)
- Install your addons (if any).
- Open your project.
- Save as project folder (in a separate folder).
- Close the current project.
- Chrome > F12 > Application (tab) > Clear site data (button)
- Install your addons (if any).
- Open your new Construct 3 project. (The one created from a separate folder.)
- Save project as new .c3p.
- Install your addons (if any).
- Chrome > F12 > Application (tab) > Clear site data (button)
- Install your addons (if any).
- Try now continuing your work.
If you want to really move on, I can understand. But, this might be useful for future users who still want to continue, just in case.