When you drag an element past its maximum area then release the mouse button, the element continues to believe you are dragging it until you click anywhere to release it.
This is most noticeable with the YouTube selection circle: dragging it to the far left and right, then releasing the mouse button, causes the effect said above.
@bigyihsuan, thank you for bringing this to our attention. I fixed it today and it will be included in the next build. I also fixed it for the volume / octave sliders in the band editor; this fix will be included when we launch 2.12 which has some updates to the band editor.