Feature/sidebar focus

[Dipanshusinghh]

Summary

This PR fixes the keyboard accessibility issue where the project sidebar could not be focused via keyboard navigation.

Changes Made

• Made Code.Sidebar focusable by setting can_focus = true.
• Added ACTION_FOCUS_SIDEBAR (action-focus-sidebar) to MainWindow.
• Bound <Control><Alt>Left to focus the sidebar directly (and opens it automatically if it is currently hidden).

Fixes #1711

[jeremypw]

Unfortunately this does not seem to work yet - focus remains with the document for me. Not sure why yet, but it does work if you focus the choose_project_button instead. So its something to do with making sure the treeview within the SourceList gets (and retains) the final focus.

Also may need a matching hotkey to return focus to the document but that can be addressed later.

I notice that if you do focus the choose_project_button then you can reach other widgets in the headerbar by using the standard Tab and <Shift>Tab keys. But not the actionbar.

[jeremypw]

I am not sure this right - Sidebar is a container (Grid) which cannot have keyboard focus itself

[Dipanshusinghh]

@jeremypw Thanks for the detailed review and for pointing out the root cause!

You are completely right. Sidebar is a Gtk.Grid container and shouldn't have can_focus = true. The issue with the focus not reaching the actual treeview happens because calling grab_focus() on the SourceList (which is a Gtk.ScrolledWindow) doesn't automatically pass the focus down to its child Gtk.TreeView

I have addressed the requested changes:-.

1. Removed can_focus = true; from Code.Sidebar
2. Overridden grab_focus() in Code.Widgets.SourceList to explicitly call tree.grab_focus(), ensuring the underlying Gtk.TreeView gets and retains the final keyboard focus

Regarding the shortcut to return focus to the document and the Actionbar tab navigation, I agree that those can be addressed in a separate follow-up PR as enhancements

Thanks again!