Brace matching is really helpful, but whenever the cursor is on one of the braces, both of them are shown in bold style (and gray color).
Can I remove the bold style?

Bold style lengthens the string and the lines start to jiggle as I
move the cursor up and down on a list of braced items.

UE 17.30.0.1002

The fonts may "lengthen" when a character is made bold in UE 17 and prior. You may want to consider using a better font, as there are many fonts that will display correctly with bold/non-bold on the same line. UE 18 is supposed to fix this issue with the fonts, and I haven't seen the same "jiggle" when testing it in version 18 with fonts that were troublesome before. I tried it with several different fonts.

However, the case of it forcing you to use "bold" for the brace highlighting is a matter of needing to send a feature request to IDM at the email address in the paragraph at the top of the forums. I will send one as well. I sent one quite some time ago, but will send in another if you plan to as well.

You can change the actual color of the brace foreground and background when braces are highlighted by going to "Advanced->Configuration->Editor Display->Miscellaneous" and clicking the button "Set Colors". You can also change it at "View->Set Colors" depending on your menu layout. Unfortunately, you can't change items here between bold/italic/underline. It decides for you. That's where we need the feature added.

The last option is that you disable the configuration setting Enable auto-brace matching at Advanced - Configuration - Editor Display - Brace Matching. That turns the feature completely off. You can use Search - Go to Matching Brace or Search - Select to Matching Brace if you need to know where the matching brace is.

Using a fixed pitch font (same width for a character in all font styles) is another option as rhapdog already wrote. See also Monospaced vs Fixed Pitch fonts. I don't know which proportional fonts are fixed pitch fonts. Many non proportional fonts are fixed pitch fonts, but I think most proportional fonts are not fixed pitch fonts.

I'm not using TTF/OPEN type font, but a FON file which I have edited to my needs.
Maybe I'll find somewhere a TTF font like that and just edit some chars, that would be best.

BTW, UE should allow changing font width. In windows, CreateFont, nWidth param.
This param is usually set to 0, but other values can be more pleasant to (my) eyes.
Default windows font selection dialog doesn't allow width change, so a custom dialog is needed.
That dialog could also have anti-aliasing enable/disable (CreateFont, fdwQuality).

aleksazr,

I have used that font you are using in my endless search for a decent font. I just couldn't use it long term, however, because of problems with bold and other issues.

I have been using Dina. http://www.donationcoder.com/Software/Jibz/Dina/

It is a FON file as well, but much better designed. Give it a try and see if it fixes your issue.

Another person has converted it to true type font, but I haven't tested it yet. http://www.geenat.com/?p=66
EDIT: Just tested the True Type. I'm sorely disappointed.

I have also sent an email to IDM requesting the configuration option to turn off bold for brace highlighting. As a matter of fact, I requested they give us the full option of "normal, bold, italic, underline". You know some people are going to want to go there.

Thanks for the link!

The Dina font has reminded me that a FON file is actually a collection of raster fonts,
and that a raster font also can have different sizes and styles. (not only vector fonts)
So I have just inserted another copy of my DOS font (with bold setting ON) and thats it.