CSS applied with a delay inside Polymer component

I have a timeline scheduler as a separate Polymer component. The dhtmlxscheduler_flat.css reference is at top of the template markup. The whole timeline scheduler initialization happens inside ‘attached’ event of Polymer component.

When I load the page, I see that scheduler is blinking with unloaded styles (as you’re missing css reference) and in a half of the second all css are fully loaded and applied. I would like to show spinner instead of un-styled, and once css are applied, show scheduler. Which scheduler events can I use for that?

Try to use onXLE event.
docs.dhtmlx.com/scheduler/api__ … event.html

My data are loaded before the css are applied, so this event doesn’t help (already tried). If I remove css file reference, I see that broken markup with loaded data. Or I can record a video and then play - I see that data with broken markup appears before the nice css are applied.

Link element has event onload, seems this is really what you need:
developer.mozilla.org/en/docs/W … oad_events