Can't (always) switch between items in the taskbar

I have enough items in the taskbar that they take up two rows. When row 1 is visible and I click on one of its items, it will instead activate a random item in row 2 and vice versa. Then I have to click the little scroll arrows to get row 1 back and try again. The random switching occurs about every 4-5 times I click a taskbar item and only when there is more than one row of items.

Just for kicks, I tried extending the height of the taskbar so both rows are visible at once, and the anomalous behavior disappeared. But I prefer to keep the taskbar one row tall.


Can this nonsense be remedied?