Fix #294: Rapidly closing tabs with three-finger/middle click button re-opens closed tabs

[felix-andreas]

Fix for #294 and elementary/code#485: Dynamic notebook: Rapidly closing tabs with three-finger/middle
click button re-opens closed tabs

Changing child_revealed to reveal_child to make tab close-able by middle/three-finger click during
reveal animation. This prevents the creation of new tabs when trying to rapidly close multiple tabs.

Before

After

[jlnr]

@andreasfelix Definitely better than before! It still happens when I double-wheelclick on the border between two tabs, though. Do you think this is can/should be fixed within the same PR?

[jlnr]

Solves the issue in most cases.

[felix-andreas]

Unfortunately I think this is a different Issue. I have highlighted the size of the GranitsWidgetsTab and logged the enter and leave events:

As one can see, the size of the GranitsWidgetsTab is slightly smaller than its visual size. This can also be seen at the event log: The signal get emitted when entering/leaving the blue highlighted area. When clicking on a Tab outside of this are, the signal gets directly passed to DynamicNotebook which leads to the restoring of the last closed tab.

I think this is related to the padding and border in the style sheet:

https://github.com/elementary/stylesheet/blob/ec23fec4a4bcd6577d2d2039eb24ae9bc9364577/elementary/gtk-3.0/gtk-widgets.css#L1670-L1688

Maybe it could be solved by changing notebook tab to notebook tab widgets grid, so the padding is within the Gtk.EventBox.

[felix-andreas]

I have a other question: What is the rationale behind the close_button_is_visible method in the first place? Why shouldn't a tab be close-able by middle/three-finger when the close_button is not visible? Is this in any way needed for pinned tabs? I ask because of the line close_button_revealer.visible = !_pinned.

Otherwise it would be simpler to just remove the private bool close_button_is_visible () from the if statement:

if (e.button == 2 && close_button_is_visible ()) { // <-- remove close_button_is_visible ()
    e.state &= MODIFIER_MASK;

    if  (e.state == 0) {
        this.closed ();
    } else if (e.state == Gdk.ModifierType.SHIFT_MASK) {
        this.close_others ();
    }
} 

[jlnr]

What is the rationale behind the close_button_is_visible method in the first place?

I have no clue. git blame leads to this commit: 13f290a

The referenced launchpad issue is about hiding the (x) buttons until you hover the tab, i.e. in the first commit where buttons weren't permanently visible.

I would guess that it was added out of unspecific defensiveness. Have you tried removing it? Does anything break? Less bugs and less code sounds good to me :)

[felix-andreas]

I have completely removed the close_button_is_visible method as it always returns true in the if statement and isn't used anywhere else.

[jlnr]

LGTM