And while we are here — how about Discretionary Line Break, http://illustrator.uservoice.com/forums/601447/suggestions/49029236 ?

Excellent. It would be great if they could make the behaviour of various spaces in InDesign and Illustrator consistent. Now the spaces have
1) different widths as mentioned here http://illustrator.uservoice.com/forums/601447/suggestions/47773844
2) different functionality (thin space in InDesign is non-breaking which is better)
3) different representation (the invisible representation of non-breaking space in Illustrator is wrong)
4) different set of available spaces (ALL standard Unicode spaces must be supported)
5) different names in Czech UI of InDesign and Illustrator (the submenu is wrong in both versions. It should say "Vložit mezeru" not Insert White Chatacter nor "Insert Empty Place".

Filip, I am told the team is aware of the discrepancy with the marker and is intended to make it consistent with InDesign.

Hi, Filip, nice having a comment form you here!
I concur, The symbol used by Ai indeed matches with the one used for Thin Space!
And yes, thin space in Ai breaks, unlike in InD, and I think this should be extracted into a separate entry.

And while we here, here is a link for the related request, Thin space and hair space have wrong widths, compared to InDesign — http://illustrator.uservoice.com/forums/601447/suggestions/47773844

Good news, thanks!
But why is the non printable symbol representing this glyph different from the one used in Adobe InDesign? The one used in Illustrator is actually used for thin space in InDesign... And while thin space is nonbreaking in InDesign, it breaks in Illustrator.
French texts require thin non breaking spaces to keep « quotation » marks together with the expression (although some people prefer standard nonbreaking space).
This is very confusing. Please make it consistent accross all Adobe apps.
(Also keeping the terminology consistent would be nice, the Czech UI is very inconsistent between InDesign and Illustrator regarding spaces.)

Illustrator should recognize a standard Non-breaking space.

llustrator ignores the nonbreaking space (U+00A0) and replaces it with the standard space (U+0020). This makes text exchange with other Adobe applications impossible, as the lack of nonbreaking space causes the inserted text to be reflowed.

In addition, the absence of this space discriminates against users of languages where this space is essential in typesetting. This is the case of French, which separates « quotation marks » and some punctuation marks with this space so that they do not remain at the beginning of the line (? : ; !). These are Czech, Polish, Slovak, Russian, Hungarian and other languages where single-character words cannot remain at the end of the line. These are languages where non breaking space is used to separate thousands in numbers (200,000 in English is written 200 000 in many languages around the world).

I strongly urge you to stop making life difficult for Illustrator users and fix this bug.

While we wait for Adobe to fix this, I use a simple scripts to enable and disable "no break". I assigned a shortcut to it with AutoHotkey

#target illustrator

var nobreak = app.selection.characterAttributes.noBreak
app.selection.characterAttributes.kerningMethod = AutoKernType.METRICSROMANONLY

if (nobreak == false){
app.selection.characterAttributes.noBreak = true;
} else {app.selection.characterAttributes.noBreak = false;}

Please fix this. This is a significant limitation in the typographical engine.

Illustrator does ignore glyph U+00A0 (no-break space). Please stop replacing U+00A0 by U+0020 (space) in Illustrator and support non breaking space like all standard apps in 2019.
If I copy-paste text from InDesign to identitcal text frame, the result in Illustrator may be different because of this VERY OLD bug.