My open orders is empty in exchange page after switching market

**Describe the bug**
If a user has viewed settle orders E.G. in market BTS/bitCNY, then switching to a market that doesn't have settle orders E.G. in market BTS/GDEX.BTC, the "my open orders" tab will be empty since it still tries to show settle orders.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'https://wallet.bitshares.org/#/account/exchange.btsbots'
2. Click on 'Exchange'
3. Click 'BTS' tab in 'my markets'
4. Click 'bitCNY' in the market list to view the bitCNY/BTS market
5. Scroll down to 'my open orders / settle orders'
6. Click 'Settle Orders'
7. Click 'GDEX.BTC' in the market list to view the 'GDEX.BTC/BTS' market
8. See an empty 'my open orders' tab

**Expected behavior**
When "settle orders" tab disappears, UI should switch to 'my open orders' tab correctly.

When the UI decides one panel should be hidden, it should activate another panel in the same group.

**Screenshots**

**Desktop (please complete the following information):**
- OS: Ubuntu 18.04 LTS
- Browser Firefox
- Version 69

**Additional context**
I think I have submitted this issue before, but can't find it right now.

Start by reproducing the issue at the exchange page for account exchange.btsbots, switching from the bitCNY/BTS market with Settle Orders selected to the GDEX.BTC/BTS market. Trace the market and tab-switching behavior in the frontend. Done means that hiding Settle Orders activates My Open Orders instead of leaving the visible panel empty.

Written by the indexing model from the issue text.