Scrolling starts at top of window, not top of scrollbar

[ThomasFrans]

Describe the bug
When using the mouse to scroll, a tiny bug causes the scrollbar to skip two blocks. It only happens when clicking on the last two 'blocks' of the scrollbar. It's not important at all, but just thought I'd make a bug report since it's technically a bug. I was playing around with the code and noticed the scrollbar gets activated when you click above the scrollbar, because the activation happens at y > 0 in ListView. This means that the activation starts even when the user clicks inside the tab area above the scrollbar. It probably gets mapped wrong, because the scroller thinks the start of the scrollbar is at y=0.

To Reproduce
Steps to reproduce the behavior:

1. Open the songs tab
2. Click in the last tab, on the last block, right above the scrollbar, and hold
3. Now the scrollbar is selected

Other bug:

1. Open songs tab
2. Click on the last block of the scroll bar. The bar shouldn't move, as the mouse is on the bar, but it jumps down.

Expected behavior
When the user clicks the mouse anywhere on the scroll bar, the bar shouldn't move. Also the scrollbar should start at an offset from y=0. (In this case 2, to account for the title and tabs)

Screenshots
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System (please complete the following information):

• OS: Arch Linux (latest updates)
• Terminal: GNOME Terminal and Alacritty
• Version: 0.10.0
• Installed from: AUR

Additional context
Add any other context about the problem here.