Clicking on horizontal scrollbar selects last line

Description

On "File Status" lower tab, when viewing the file changes, if the content of a line exceeds the container width, the horizontal scrollbar is visible. By default, no line is selected, and the button "Stage hunk" is visible.  Dragging the scrollbar handle shouldn't affect the selection of the lines, but it does.

Problem:
Cliking on the horizontal scrollbar to drag it will select the last visible line, and desselect any previously selected lines.