[feature] Allow to select an open graph to explore paths

[martinec]

Is your feature request related to a problem? Please describe.

PR #123 introduces a redesign of the explore graph paths frame

Describe the solution you'd like

It would be worth if the user can choose a graph among those already open.

Describe alternatives you've considered

The approach to track open graphs is already implemented on the Find and replace dialog thorough the use of an observer pattern.

[selgueti]

To implement this feature, I need to modify three files.
Do I open three PRs (one per file) to apply Google’s Java styling and a fourth to apply changes, or one PR for styling all three files and a second for changes ?

[martinec]

You are not supposed to make changes to the code style of a whole file except when your changes modify it completely. That being said, yes, you must open two PRs : 1) refactor and 2) feature.

It is nice to know that you are working on this feature!