WSC 5.0.1 sometimes has problem with closing dialog on IE10

[msamsel]

Testing Environment:
WSC ( 80edea8 (tag: release.5.0.1.1) ),
CKEditor4 (4.10.0)
Tested on VIrtual Machine (Win7 with IE10)
Editor build from https://github.com/ckeditor/ckeditor-presets (major branch)

Under IE10 when "Finish checking" is clicked, dialog can hang and is not automatically closed.
Problem is not observed every time. When I click fast enough after opening dialog, then issue appears. Below short movie how it looks like.

[AAbakumov]

@msamsel Thank you for reporting this. We will check this issue on our-side and get back with comments.

[jshaptala]

@msamsel,

We were able to reproduce the issue following the steps to reproduce. This is a very uncommon use case and can be reproduced only in cases with actions that are performing very quickly, and only for IE10. The issue caused by our intentional postponing of certain actions of WSC/SCAYT plugins to allow CKEditor to complete certain required actions.
Our attempt to make a quick fix hasn't eliminated the issue totally, it can still be reproducible but more rarely.
At this point, considering specifics of the issue (only IE10 and uncommon use case) in order not to affect the behavior of CKEditor, this issue won't be fixed.