for an iOS app I'm using Delphi 10.3.3 and the TMSFMXMemo from the TMS Pack for FireMonkey v3.7.2.6.
When using the font "Courier" the text displays/behaves normal.
Changing the font to "Courier-Bold", "Menlo-Regular" or "Menlo-Bold" the TMSFMXMemo behaves as if the selected font is not fixed (proportional): the selected text is shorter than the colored background of it.
How can I select the font eg. "Menlo-Bold" and make the TMSFMXMemo behave as if the font is fixed (what it actually is).
We have investigated this here, and can see an issue when setting the TMSFMXMemo1.Font.Family to "Menlo-Regular", but as the property indicates a family needs to be set, you can set TMSFMXMemo1.Font.Family := "Menlo" to fix the issue. If you want to have a bold Menlo, you need to set the TMSFMXMemo1.Font.Style property.
I suspect you have a syntax styler assigned to the TTMSFMXMemo and when so, the font style is adopted from the styler, i.e. its value will depend on the code in the memo.