Vaadin 7: often IllegalStateException on resize


Using Vaadin 7 (alpha 2 and snapshot) I often get this error message on browser window resize:

“IllegalStateException: Can’t start a new layout phase before the previous layout phase ends.”

What does this mean, what typically causes it, and how is it solved? Or is it a Vaadni 7 bug?


It means that the framework thinks a layout phase is already going on when a new phase is about to begin. The cause for this is either that the previous layout phase ended abruptly (e.g. an uncaught exception) without properly marking itself as ended or then there’s some part that triggers a new layout phase when another phase is already going on.

The problem could be caused by almost any client-side code that is related to components. If you used any add-ons, could you see if the problem also occurs without them?

Stack traces (directly available with Firefox, indirectly accessible in most other browsers by setting a breakpoint on the javascript that throws the exception) from a pretty-compiled widgetset or from running the client-side code in GWT development mode would significantly help pinpointing the problem.