Default exchange setting

[kakulukia]

This is also partially a bug report.

I was closing a candle import tab and now im flooded with those messages.

Turns out i should have hit the cancel button before closing the tab.
But how did i end up in this situation?
I wanted to import multiple symbols, but opening a new tab always bring me to one that has Binance selected as the first exchange in the list. Could we have a setting to define the default exchange, so this will be respected for new tabs?

It kind of works in backtests as Jesse seems to always clone the current tabs content which is very neat to make one more test with just one value changed. That could also be done with candle import.

But the mentioned default exchange setting would more or less guarantee that i will not accidentally end up with a wrong exchange in any of candle import, backtest, optimization and live modes.