[BUG] Scrollbar behaves unexpectedly

[mjk-gh]

Rofi version (rofi -v or git commit in case of build issue)

2.0.0-27-gb905f073 (next)

Configuration

https://gist.github.com/mjk-gh/c64fd5377e11e3d07d0fac0c81f3f527

Theme

https://gist.github.com/mjk-gh/0ad12ee4e7e82dc397964a8406d64e8a

Timing report

No response

Launch command

rofi -show-icons -show window -normal-window

Step to reproduce

Launch rofi as described above.

Expected behavior

• Scrollbar area corresponds to length of complete window list
• Scrollbar length corresponds to length of visible part of window list
• Scrollbar position corresponds to position of viewport of window list
• Moving scrollbar moves viewport of window list, but does not move the selection bar
• Clicking with the left (or a different) mouse-button in the empty areas above and below the scrollbar moves the viewport page-wise on each click.
• Clicking with the middle (or a different) mouse-button anywhere in the scrollbar area places the middle of the scrollbar right under the mouse cursor.

Actual behavior

I opened 30 windows. As rofi shows 15 windows at a time, the scrollbar should have a length of exactly half the length of the total scrollbar area. Instead, it is significantly shorter, suggesting there are more than two 15-item pages, which is not the case:

Moving the scrollbar with the left mouse button (by clicking in the scrollbar area or by dragging the scrollbar) moves the selection bar as well.

Page-wise scrolling with the mouse is impossible, each click with the left mouse-button places the middle of the scrollbar right under the mouse cursor. Middle or right mouse-button do not seem to do anything.

Maybe there is an ingenious rationale behind all this, but for now, I would consider the scrollbar behavior a bug. :-}

Additional information

No response

I've checked if the issue exists in the latest stable release

• Yes, I have checked the problem exists in the latest stable version

[DaveDavenport]

I never use the scrollbar myself, but it indeed looks like it is acting up.

[mjk-gh]

Oh, one more thing: Having a wrap-around for scrolling (at least for the mouse) is at least very uncommon. Hm, maybe an option for enabling a wrap-around for mouse and an extra option for wrap-around for the keyboard?

[mjk-gh]

I just noticed this in #490:

For this the scrolling should be uncoupled of selection.

[DaveDavenport]

I think that is the source of confusion, the position off the scrollbar is the position of the selected item in the complete list.
Scrolling moves the selection, not the scrollbar (it will move, but different cause).

This is also the reason why the scrollbar is full when 10 items are shown, on a 10 high window.
Then the scrollbar is ~50%, so it is still able to visible indicate the position within the page.

To 'fix' most of the issues would require us to 'uncouple' scrolling from selection.