Currently, if some input is invalid in the generated custom forms, YAWL will give you an error like this:

In fact for dates the validation is different. From our experience with people unfamiliar with YAWL the way date validation errors are displayed are rather subtle. Especially if you had previous validation errors in other fields or if you have a long list of fields to fill out:

As you can see, the error is show on the left side of the field, but in cotrast to the pop up, that you have to click away first, this is harder to see. For a unified validation error system, we propose that date errors should be displayed in the pop up as well and colored red.

Do some of you have experience with people using YAWL and having problems when it comes to date validation? We would like to know if you think, that this is a relevant problem.