Strange bug of the program?

[Philipp]

 Hello! I may ask why composite symbols formed by negative factor scaling (see red ellipse) are displayed correctly in the viewport (see blue ellipse), but in many other programs they are incorrect.

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 So, for example, even in the FontCreator itself in the text field "Note" the window "Font Properties" (green ellipse) or in Excell (orange ellipse). Why do such characters break the order in a string? Is this an uncorrected bug of the program? or can something be done about it?

[Bhikkhu Pesala]

It is recommended to decompose scaled composites on export. This option may not be available in versions older than FontCreator 13.

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[Philipp]

 Thanks for the tip! In version 14, this option has been moved to the font export settings window.

[Philipp]

 Oh, yeah. Only in this case, the size of the font file begins to grow by leaps and bounds. After enabling this option, the program decomposes all composite glyphs. And the main meaning of composite glyphs is lost.
 This turns out that if the size of the font file is important, you need to manually check each composite glyph whether it will be displayed correctly in other programs. In this case, the font preview window is of little use. It looks like this is a serious flaw in FontCreator. And the user is not aware of this in any way.
 Can anyone tell me under what conditions the composite glyph won't slide down the line? After all, not always with scaling composite components such a bug appears.

[Bhikkhu Pesala]

If there is any flaw at all, it is in the applications that do not support scaled composites.

FontCreator 14 offers several options in Export Settings. If I choose Decompose All, it bumps the size of my font from 1,327 kb to 1,541 kb, which is barely significant.

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If you are keen to save on file size, remove character hinting, and use WOFF2 format for websites, where file size is an issue.

[Philipp]

 Thanks for the advice. Only my file size has grown from 500 kilobytes to 700. And that's far from the end. The problem with file size is that a number of programs do not want to work with font files that are larger than 1 megabytes.
 In addition, as the font file size increases, word processors begin to eat a significant amount of RAM. And this, in turn, makes it impossible to use them, for example, on mobile devices or old computers.
 In certain cases, your hint solves the problem. However, in fact, this is not an option. This is not serious for professional software.
 However, a solution of the problem is possible, because not all glyphs with scaled components are problematic.

[Philipp]

 Hurrah! Found a solution! Blessed is He, Who gives wisdom to man!
 To ensure that composite glyphs with scalable components do not violate the order of characters in a string,
 

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and displayed correctly in any program (without a decompose operation during compilation to reduce the size of the font file)
 

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one need to create an additional glyph and insert a zero-length path into it. To make this path invisible when displaying symbols.
 

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And then add this symbol as additional components to the problematic composite glyph on the left and right outside the other components.
 

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I don't know why, but it works. Now, humph , there is a lot of work to be done to correct the mistakes made due to ignorance.
 
The developers of the FontCreator should have respected the buyers of the software. After all, they are well aware of this problem. They could warn at least in the help documentation to save the user from stupid correction of the work done and the loss of so much time and effort.