Created attachment 103112 [details] Video showing the problem The icons show in the Folder View widgets extend to the desktop space beyond the boundaries of the widget, e.g. say the folder widget's boundaries are from coordinates X1,Y1 to X2,Y2, the icons even show in the space at coordinates >X2 and >Y2. During resizing of the widgets, however, the icons only show within the borders of the widget. When releasing the resize icon, the icons show again in the area they shouldn't be (see attached video).
The reason why they don't show up during drag is there the container clips its content to avoid contents leaking outside when the applet hasn't resized yet. The issue is though that the FolderView applet layouts its icons the wrong way. Any notable settings you have? Can you add your plasma-org.kde.plasma.desktop-appletsrc? I can't reproduce the issue here, though.
Created attachment 103143 [details] Config file Added my plasma-org.kde.plasma.desktop-appletsrc.
Thanks for the update.
I updated my distribution now to openSUSE Leap 42.2 and now the folder widget is OK again. From my point of view, this one can be closed.
Thanks for reporting bad, glad it's working now.