Hiding Filter bar = leftover empty horizontal bar

[gboudreau]

• Sequel Ace Version: 2.1.0 beta 3
• macOS Version: 10.15
• MySQL Version: N/A

Description
When the Filter UI is hidden, some of it is still visible.

Steps To Reproduce

1. Navigate from table1 to table2
2. Show filter bar in table2
3. Use the history arrow to go back to table1

Expected Behaviour
Filter bar should be completely hidden.
Right now, there is one of the two horizontal views, the one with the Filter button, that is still visible), but empty.

Additional Context

[gboudreau]

The filter bar should NOT disappear, when switching tables. So the bug is actually that it disappears, not that there is leftovers.
Will close this issue, and track this bugfix in #80.