some Windows do not appear in the panel

Submitted by vladimir

Assigned to Nick Schermer

Link to original bug (#14394)

Description

Created attachment 7723 screenshot

Mistake is happening in a random way (can week enjoy the system and not meet its,and can and for couple of hours several times its see). For example,I open one window,the second ,the third ,then close the first or the second, but the indicators of open Windows do not shift to closed... don't know how to explain it...see screenshot....

the screenshot shows-thunar was opened,it was copying files, then I closed the main window thunar ,and in its place on the panel remained void

Attachment 7723, "screenshot":

Version: 4.13.3