InDesign CC 2017 closeExtension() does NOT work properly.

Hello all InDesign experts.

We have an HTML/JS Extension since version CC 2014 (or CSXS 5), which works also just fine for CC 2015.

In this we have some progress panels to show processing percentage. As all steps are finished, the panels are closed programmatically with: CSInterface.prototype.closeExtension().

All functional on CC 2014 and 2015.

BUT as we switched to CC 2017 this function does NOT work as expected any more. It does clean all contents within the panel, but the empty panel frame kept shown until the user clicks "x".

FURTHERMORE a panel is not closed completely via closeExtension() when it's defined as <UI><Type>Panel</Type>... </UI> in manifest.

If the type is changed to <Type>ModalDialog</Type>, the function closes the whole panel as it used to be.

We tried CSXS 5, 6 and 7, all act the same.

Anyone else is facing/faced the same problem and can give us some information how can we fix this?

Thx a lot.

PS: Originally this question is posted on a different sub-space. Tip from nice forum members should I try my luck here.

In case anyone is interested for this problem and someone is able to solve it in another thread. Click me.