Form failed to load in designer with a SessionExpiredError

[p.colbert]

You typically don’t want that code to run in the IDE, at Design time. For a way to prevent that code from running, at this wrong time, see the “as-yet-undocumented but useful feature” here:

Question about Custom Components in Beta Designer

Ah, that would do it! There’s a limited set of modules available inside the designer, but we’ll add anvil.tz to it However, here’s an as-yet-undocumented but useful feature: You can write: from anvil.designer import in_designer and now you have a boolean variable called in_designer, which you can use! So for example, you could replace your import anvil.tz with: from anvil.designer import in_designer if not in_designer: import anvil.tz Then you won’t get the ImportError in the d…