> in here "Miscellaneous Technical"
>
https://en.wikipedia.org/wiki/List_of_Unicode_characters#Miscellaneous_Technical
> firefox shows almost all of them
> konqueror shows almost none.
> 

Indeed I do not see the same as in firefox. [...]

IMO it is a combination of font and rendering. Can you try with kcharselect?

I can see the symbols with 

Font: Liberation Mono   (or most mono type fonts)
Table: 35
Unicode: 2300

For example the math symbols are visible with
Font: Latin Modern Sans Quotation       (or most sans type fonts)       
Table: 34
Unicode: 2200

Check if you have all needed fonts installed. When I was using LaTeX I
installed many additional fonts. I replaced the PC with newly installed
since, so might be they are missing here again.

Check also the default fonts setup in TDE.

-_- ....
crap, the site ate all my post after the character "grapes" U+1F347 and didn't noticed....
i had "grapes" at the end of the title too....

I'm on linux mint 18.2 mate 64bit
i can see the grapes in xed, libreoffice, firefox, vlc, kiten and synaptic. 
But in none of trinity apps.....

$ echo "$LANG"
en_US.UTF-8

with kcharselect
what your saying seams correct.
configuration seams correct....

OK, so we can conclude that konqueror does not pick up the correct font to display the characters. It seems like a valid hypothesis.

The statement
"i can see the grapes in xed, libreoffice, firefox, vlc, kiten and synaptic. 
But in none of trinity apps....."

seems contradictory - do you see this in kcharselect?

please confirm

besides this kcharselect can only handle 4digit code and what you stated (U+1F347) is 5 digit. I don't know how it can be displayed in kcharselect.

Most likely there needs to be some update to handle this.

yea kcharselect stops at FFFF ....

in control center
standard fonts: Sans serif
default encoding: "use language encoding"

i can see the grapes and other stuff in the apps i'm mentioning, but not in trinity apps (kiten has a qt4 version)

Not in:
konsole, kate, kwrite, konqueror, kmail, klipper......

i also tried trinity apps from inside mate. same result.

I think we narrowed down the problem. Someone needs to find time to look into the code and decide what needs to be updated.

thanks so far and regards

I've noticed something like this for a while but thought it was just my machine.  In my case I can't see symbols like TM (™) in TDE applications.

Can you confirm that you are unable to see the "™" symbol in TDE as well?

Thanks!

I can actually see "™"
tried konsole, kmail, akregator, kate.....

(™) is U+2122 and is visible in kcharselect, so it should be visible in the tde apps (assuming you have the proper font)

Font: Sans Serif       (or most sans type fonts)       
Table: 33
Unicode: 2122

It is also visible in konqueror - try https://en.wikipedia.org/wiki/List_of_Unicode_characters#Letterlike_Symbols

However there is significant difference between konqueror and kcharselect. In konqueror you see a fraction of what you see in kcharselect

man tqchar

So to fix this we should fix tqchar to handle size bigger than U+0000

       The QChar class provides a lightweight Unicode character.

       Unicode characters are (so far) 16-bit entities without any markup or structure. This class represents such an entity. It is lightweight, so it
       can be used everywhere. Most compilers treat it like a "short int". (In a few years it may be necessary to make QChar 32-bit when more than
       65536 Unicode code points have been defined and come into use.)

       QChar provides a full complement of testing/classification functions, converting to and from other formats, converting from composed to
       decomposed Unicode, and trying to compare and case-convert if you ask it to.

       The classification functions include functions like those in ctype.h, but operating on the full range of Unicode characters. They all return
       TRUE if the character is a certain type of character; otherwise they return FALSE. These classification functions are isNull() (returns TRUE if
       the character is U+0000), isPrint() (TRUE if the character is any sort of printable character, including whitespace), isPunct() (any sort of
       punctation), isMark() (Unicode Mark), isLetter (a letter), isNumber() (any sort of numeric character), isLetterOrNumber(), and isDigit()
       (decimal digits). All of these are wrappers around category() which return the Unicode-defined category of each character.