Size of Form and controls is bigger in WinForms .NET Core app compared to WinForms .NET Framework app

[bairog]

• .NET Core Version: v3.0.0-rc1
• Have you experienced this same bug with .NET Framework?: No

Problem description:

1. Using Visual Studio 2019 16.3 Preview 4 create a WinForms .NET Core app and a WinForms
   .NET Framework app, which have same designer code with some controls added.
   WinFormsFrameworkApp.zip
   WinFormsCoreApp.zip

2. Build and run these 2 apps, and compare size of forms and controls

Actual behavior:
Size of Form and controls is bigger in WinForms .NET Core app compared to WinForms .NET Framework app (for example Form is 1178x799 pixels on .NET Core 3.0 and 1010x697 pixels on .NET Framework 4.8)

Expected behavior:
They should have same size (pixel by pixel identical).

[bairog]

In all my form controls I don't use Segoe UI 9pt, I use Calibri 12pt.
Why my forms are not pixel by pixel identical in that case?

[bairog]

Let me clarify - for example in both projects:

1. Form size in designer is set to 1028x706 (font is Calibri 12pt)
2. Button size in designer is set to 70x28 (font is Calibri 12pt)
   .NET Framework 4.8 app respects that sizes, while .NET Core 3 app is bigger than that values..

[RussKie]

I believe the result is due to this line:

this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);

If you comment it out, it renders the form in the same size.

Here's the relevant info: https://docs.microsoft.com/en-us/dotnet/api/system.windows.forms.containercontrol.autoscaledimensions?redirectedfrom=MSDN&view=netframework-4.8#remarks

@OliaG this may trip a few people, perhaps we need to highlight this somehow.
/cc: @merriemcgaw