Created attachment 1101793 [details]
logs and screenshot

Description of problem:

I switched between detailed view and summary view without waiting for results to show and I got an error that disappears after 10 seconds:
Error building timeline Task has been queued
Since there is no sign for the user that anything is actually happening with the request I think this would happen for impatient people such as myself

Version-Release number of selected component (if applicable):

cfme-5.5.0.13-1.el7cf.x86_64

How reproducible:

100%

Steps to Reproduce:
1. navigate to containers -> providers ->select provider
2. select monitoring -> timeline
3. in the "Level" scroll switch between summary to detailed and back to summary (without waiting for results)

Actual results:

we get a flash error: Error building timeline Task has been queued

Expected results:

Any of these would be fine: 
1. add a sign that the request is being handled
2. do not allow moving between the scrolls as long as a request is in process
3. ask user if they would like to cancel request
4. change error message to something clearer.

Additional info:screenshot and logs