There is "Manage source editors" in the main menu "Windows". Which allows double click, and which has a filter. But does not group by package.
The "
Manage Source Editors" window is very convenient. It appears when you press "
[Ctrl+Shift+W]", and you can immediately enter part of the file name in the filter.
To open any project unit, you can use the "
Main Menu > Project > Units" window, which appears when you press "
[Ctrl+F12]".
Another very similar window is "
Main Menu > File > Open Unit", with the combination "
[Alt+F12]". It allows you to open files not only of the project, and I use it all the time.
Note that the last two options allow to open not only a tab, but also files that have not yet been opened. And each has its own other features.