You can do this with the field visibility scheme as they are.
Allow the developer and customer to see Field 1 (Ctrl + Click on the groups) and only developer to see Field 2.

Or have I missed the point here?

Or have I missed the point here?

Yes, in this case developer will not see Field 1 at all, and I need that he can see it but is not allowed to edit.

You have now: Field Visibility Scheme=Field+Group*N

So many groups could be configured to access one Field.

The mean of "access" is defined then for each Issue Type you set for each Issue Stage (Create/Edit/View/Comment) some Field Visibility Scheme.

The main problem here is that ALL the user groups configured in Field Visibility Scheme have equal rights for example, to Edit the field.

And I need something like Field Visibility Scheme=(Field+(Group+Stage)*N) So for one fiield should be possible to configure MANY records of Create/Edit/View/Comment permissions for several Groups, that the Client can only view the field and Developer can view it and ALSO edit it.

Remember field visibility scheme applies at the issue type level for view, edit and create.
So you can allow the developer to see a field but not edit it, same for a customer etc...

That's true, but I need to distinguish the permissions to create/view/edit for the different roles for the different fields inside ONE Field Visibility Scheme.

Consider the following example:

I have Field 1, Field 2 and Field 3. I have groups Clients and Developers.

I need to configure the following:

a) Field 1 and Field 2 are visible to the Clients on the view page, Field 3 not. All the 3 Fields are visible to the Developers.

The first part is easily configurable by creating Field Visibility Scheme "A", switching on Checkboxes near the Field 1 and Field 2, choosing both Clients and Developers and then assigning this Scheme for the View Issue mode on Issue Type Configuration page. But how can I allow here only Developers to see Field 3 on the view page for the same Issue Type?

b) Field 1 is visible to the Clients on the create page but not visible on edit page (he can fill this field while creating issue but then is not allowed to change it). And Field 1 is visible to the Developers for both create and edit pages.

Here the same situation. I can not allow for the Developers only to edit Field 1, because the Field Visibility Scheme "B" which I configure for Edit mode have inside equal rights to edit for both groups for the dedicated field. So I can configure either Developers AND Clients to edit the issue, or none of them, as I can not create two different Field Visibility Schemes one for Clients (without Field 1) and second for the Developers (with Field 1) and assign them BOTH to ONE Issue Type for the Edit mode (this could solve my problem).

That is quite simple:

a) In the field visibility scheme for view, set Field 1 & 2 as you've said and tick field 3 selecting the Developers group only.

b) Set a new field visibility scheme for CREATE for the type(s) and make sure that clients and developers see Field 1.
Set a new field visibility scheme for EDIT for the type(s) and make sure that only Developers see Field 1.

That's it. Feel free to send us an email (support at countersoft dot com) and we can do a GoTo meeting session to show you how to do this.

Yes, this works, thank you!

I also noticed, that if I set for some standard field like e.g. Issue Title only Developer and assign this Schema for Edit Mode, then Client can see this field also on Edit page but this field is disabled for editing.