Listbox no longer scrolls when dragging outside widget

[mooffie]

The listbox widget contains code that makes it possible to scroll the list by dragging the mouse outside (above or below) the widget. Here is its gist:

static int
listbox_event (Gpm_Event * event, void *data)
{
    ...
    ...

    if ((event->type & (GPM_DOWN | GPM_DRAG)) != 0)
    {
        Gpm_Event local;
        ...

        local = mouse_get_local (event, w);
        if (local.y < 1)
            /* scroll up */
        else if (local.y > w->lines)
            /* scroll down */

However, this feature stopped working with commit 33d25a0c8f (from 2011), which added the following two lines at the start of the mouse handler:

    if (!mouse_global_in_widget (event, w))
        return MOU_UNHANDLED;

I.e., if the mouse is outside the widget, the function exits. So the function no longer sees dragging events occurring outside the widget.

[mooffie]

(I don't know why the code is shown jumbled. I did use "{{{...}}}". If anybody figures out what's the problem let me know so I won't repeat it in the future.)

[egmont]

Do you really mean dragging, not scrolling? What do you do exactly? Do you click inside the widget and then move it out?

[mooffie]

Replying to egmont:

What do you do exactly?

To see the problem, open a dialog containing a listbox with gazillion items. E.g., open the editor and choose "Syntax highlighting..." from the "Options" menu. The listbox there is huge.

Now:

• Hold down the left mouse button over an item. Don't release it.
• Move the mouse down (an action called "dragging") past the listbox's south border.

The listbox should now start scrolling. It doesn't.

[egmont]

I see, you're totally right!

[mooffie]

This bug vanishes if ticket:3571 gets accepted (see comment 2 there).

[andrew_b]

Fixed in #3571.