1) How can I turn off the animations (as user or global).
It cost me and new users a lot of time going trough the trees, searching for some toppics, if they are not jet in the favourits lists (thank you for that), because it is not shown the full tree anymore where I can select other toppics directly.

It is not possible to remove the animation.
We'll have a look if we can introduce parameter to accelerate it.
NB : when you search for topics, use the search menu feature

2) Global parameters --> display in fading mode Yes/No
What does this setting change? I couldn't see any differnce neither in Firefox nor in edge...

This is not used anymore.
This parameter was removed from user parameter, but left on global parameter. This will be fixed.

3) How can format of the representetd dates be changed into MM.DD.YYYY

This is a user parameter

4) Where to check if comma "," or dot "." is used for numbers?
(I've seen in the Forum that in some configuration it might be ",")

It will change automatically depending on behavious on your browser

5) How are the colors chosen? Some combinations of main and secondary color lead to results where for example the arrow cannot or hardly be seen anymore. (specially for people with a color weekness).

We propose 4 exemples, but everyone can define his own color, to fit enterprise graphic chart or to fit own taste or to distinguish connected user or instance
Note that default selection on global parameters will be displayed as 4th proposed values, to adapt to brading colors.
 

Thank you for the reply

Unfortunatley the date canno't be formated at the user parameters. It only accepts the following predefinde three formats
MM/DD/YYYY
DD/MM/YYYY
YYYY-MM-DD

3) How can format of the representetd dates be changed into MM.DD.YYYY

This is a user parameter
 

By the way:
Is it forseen for the left hand menu, that only selected topics and topics with subtoppics change the collor? Or should also the topic which is below the mouse change the collor, if it has no subtoppics (select frame). In the moment it shows teh star to select as "favourite"

I did'nt notice you want . (dot) instead of / (slash).
No this cannot be changed.