Question: problems using style sheet with Maple

I am having hard time understading how a style sheet works with Maple. I am trying to use the "document mode" and would like to change the font used for math.

The first question I have is: How does one determine which style sheet is being used for the current open document?

Second: I have followed instructions on how to make a custom style sheet, as shown here: https://www.maplesoft.com/support/faqs/detail.aspx?sid=87675 and saved the style sheet on some location on my PC.

But it seems to have no effect at all. Since when I load it again using Format->Manage style sheet->User defined style set, then using the Browse... and select the file my_style.mw which I created using above instructions, I notice that fonts remain the same. I also close Maple and start again, and select my_style.mw again, but when I start typing in document mode, the font is still italic, even though in the XML I see it says  talic="false" (when I open the file in text editor):

<Font name="2D Math" background="[255,255,255]" bold="false" executable="true" family="Times New Roman" foreground="[0,0,0]" italic="false" opaque="false" readonly="false" size="12" subscript="false" superscript="false" underline="false" placeholder="false"/>

I even tried editing the style sheet I think Maple is using, by hand (it is an XML, and modified the font to be not italic) and reloaded it, and no effect. I even added invalid entries in there, and invalid font names, just to see the effect, and nothing happens, no error or anything. It is as if Maple does not even read the style sheet I just saved.

All what I want to do it to make the math 2D input, be _not_ italic font. I spend one hr on this, and nothing seems to make any difference, Maple insist on using italic for math input when in document mode.

Why is it that the style sheet says talic="false" for 2D math, but when I start to type, it types as italic?

As you can see, when I type, it switch to italic, even though the style sheet I just set, it clearly saying italic=false. There is not one single italic=true in the whole XML file. Why is Maple insisting on using italic?

I am using Maple 2016 on windows.