[IE] Paragraph format not reflected on selection

[Garry Yao]

1. Load replacebyclass sample;
2. Put cursor in the heading line;
3. Open Format combo and select the H2 format

• Actual: H2 format is not immediately reflected after combo is closed.

[Garry Yao]

Regression of ​b46dd71817 (Prevent incorrect combo's state change on selectionChange thrown after it's opened.)

[Piotrek Koszuliński]

But it's caused by selectionChange not fired after style is applied. Or this event is fired when combo is still opened.

[Garry Yao]

Yeah, this event is fired when combo is closing down, that's not wrong though.

I proposed another fix for #9487 at t/9529.

[Garry Yao]

Pushed one commit to address #9508 as well.

[Piotrek Koszuliński]

I'd like to see some docs there, because it took me some time to figure out why do we need lastState :).

[Piotrek Koszuliński]

Oh - and reformat if () {, please.

[Garry Yao]

Fixed on master with:

​https://github.com/ckeditor/ckeditor-dev/commit/28fddcdc3b24f88f34bc8f5145ba5f5a0bc4a955