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## Summary of the Pull Request
Implementation of #6219 with a small tweak, not just passing the keys when no panes are present, but passing on the keys when there is no other pane to move to. This enables another usecase: 2 panes in terminal split vertically; in one of these panes running tmux with two panes that are split horizontally. This allows the user to still navigate between tmux panes even though they have terminal panes open.
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## References
Not that I know of
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## PR Checklist
* [x] Closes#6219
* [x] CLA signed.
* [x] Tests added/passed
* [x] Documentation updated. I don't think that's necessary
* [x] Schema updated. N/A
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan.
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## Detailed Description of the Pull Request / Additional comments
Implementation by propagating the boolean indicating success of moving focus all the way to the action handler, where this result will determine whether the action will be considered handled or not. When the action is not handled, the keychord will be propagated to the terminal.
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## Validation Steps Performed
Manual testing; all relevant unit tests still work
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