When the issue summary table is reloaded from the server, the tab and

reviewer drop-down filters would get reset to defaults, since we were

just replacing the old element with the new one. This could lead to

disruption when trying to review issues while the server is loading

content.
The table now restores any existing state, if re-rendering or reloading

from a new element. It won't just assume the state in the HTML is

correct, and it won't either skip or completely override the reviewers

filter.

Unit tests pass.
Manually tested reloading the issue summary table after changing filters,

and verified the element and internal states were correct.