Visor Sidebar's width may reset (often)

Hello.

This was happening for a very long time now, but I always forgot to ask about it.

Sometimes, the sidebar’s width on the Visor may reset (unsure if this happens with normal windows, as I almost always use the Visor).

Consider the following scenario (narrowed sidebar width):

in which afterwards, the visor is closed and one continues doing tasks, and then they double click an external hard drive icon on the desktop, “500GB”, which may yield this result:

Of course, after closing this tab, one gets:

but if the sidebar were to be re-resized back, then after closing this tab, the width would remain narrow:

(OSX 10.9.5 on a mid14 rMBP 15")