Sprint planner board not filtering

[Leopold van Lynden]

I pretty much have Advanced Roadmaps doing everything I want except filtering out certain projects from the board that I need to draw from. We have a company sprint planner board which includes two types of projects, 1) Projects, 2) Retainers. These are differentiated by "Project Category" in JIRA. When I choose the relevant board in the initial config, I would like to filter so that it only pulls in "Project Category = projects". I can manually remove the projects but after syncing with JIRA they start to reappear. 

In the initial config there are four or five steps where I would have thought this was possible but it doesn't seem to work:

1. Issue sources 

If I choose the board AND a filter that only pulls this project category it makes no difference - all pull through. I assume that's because the "filter" doesn't filter the sprint planner or something?

2. Releases

I choose the relevant releases for only the projects I want, doesn't filter them out when complete

3. Issues 

You get an option to choose which issues you want to pull through. I de-select all, then one by one choose the projects I want, and click Select all for those - it still pulls through other projects that I don't want. 

What am I doing wrong here? Seems basic and apologies if it is! Thanks for any help in advance.

[Leopold van Lynden]

Just to follow on to the question here, if I have a board with 40-odd projects, but only want to pull in the "Website Build" ones (differentiated from "Retainer" via Project Category in JIRA, shouldn't that work with a filter from Issue Sources?

I find that even though I have the additional Filter (which essentially allows only "Project Category = Website Build" it doesn't do anything, and eventually through syncing, the retainer projects will just start pulling in. Any ideas? Thank you in advance!