For data entry forms (and even some reports) its pretty important to keep contributors focused on their specific task. Its especially easy for users who are not familiar with OLAP or PPS to be confused by some things: "TimeDataView" and "Business Process" are two dimensions in particular that are just not relevant to expose to contributors most of the time. To create a data-entry form with a writable region, however, its necessary to use each dimension in your matrix, so let’s see what we can do about this...
Here's a matrix with some distracting filters – the highlighted ones that most contributors don’t need to know – at least for this hypothetical scenario:
Now lets go to the report properties editor, where when you select a filter some properties can be edited:
Marking the distracting filters hidden will hide it in the Excel worksheet, but not the filter popup dialog:
Marking a filter locked will hide it in the filter popup dialog:
Marking a filter hidden and locked will hide from both the worksheet and the popup:
In the authoring UI the filter is always shown, which concerns some people. In my experience, it looks like not a lot of contributors are distracted by this. They focus on the areas in the workbook where they are working. And when they do need to change filters they use the popup, and so don't see the "extra" dimensions that can be confusing. (There’s no way to disable the authoring UI for certain reports or for assignments. Users should be able to still use authoring to create their own matrices. And there are valid scenarios to allow them to edit even the data-entry matrices for their ease. Probably in a future version though there will be a way to lock specific matrices added - at least in assignments for the scenarios where users don’t need to make any changes. It's a relatively common request anyway - but of course I can't make any guarantees.)