Change Tracker from MainAreaWidget back to ConsolePanel

[KsavinN]

References

Fixes #7648. Fixes #7726

Code changes

Back to ConsolePanel Tracker. ConsolePanel now is extended by MainAreaWidget, have access to toolbar and content as NotebookPanel.

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[afshin]

Thanks @KsavinN! I pushed these two changes to your PR:

• Removed the content instantiation option and directly create it in the super(...) call.
• Changed isActivate back to activate because the option is meant to signal "whether to activate the console", which is an action, not a state.

But this one is still broken. I will take a look later, but if it isn't done by Thursday, we can look at it together, perhaps.

• The console does not restore itself.

[afshin]

The console restoration logic is broken. Everything else is 👍

[blink1073]

Thanks!