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The comma button being interpreted as dot in classic NAPA is due to motif enforcing your cultural settings to use period for separator.
This is not used in NAPA Engineer, because Engineer supports commas as separators for example in the Table Editor UI, if this is something set on the operating system level at Windows.
This can be changed in:
"Control Panel > Region > Additional settings. On the Numbers tab, modify the "Decimal symbol" field"
Note that this affects all of your software to use periods by default.

I can understand that writing numbers e.g. in command line and text editor can be tricky, because there commas mean very different things.
And for users using numpads, this can be quite frustrating.
We will discuss this with Engineer team and look for possible ways to improve the situation.