Created attachment 847547 [details]
After remove case from plan, case number show in cases tab does not changed except refresh the page

Description of problem:
As subject.

Version-Release number of selected component (if applicable):
v3.8.6-1

How reproducible:
100%

Steps to Reproduce:
1.User enter a test plan detail page, of which the plan has 3 cases.
2.Choose all cases in cases tab, then click 'case-remove' link.
3.Without reresh the page, Check the case number show in cases tab.

Actual results:
System show the case number is still 3. Refresh the page, the number become 0.

Expected results:
System show the case number is 0 without refresh the page.

Additional info:
The above issue also happened when in the Reviewing Cases tab.