Selectable proposals in sender view misses proposal id

[robinharms]

To reproduce:

Within regular agenda view:

• Create a proposal (Prop ID #example-1)
• Create another proposal and add the tag #example-1 to link the two

Filtering in agenda view works

Within sender view:

• The tag #example-1 appears as "other tags"
• Selecting the tag only selects the second proposal, not the initial one

[schyffel]

What's the expected behavior here?

1. Prop id tags are not shown in other tags (Previously intended behavior)
2. Prop id tags are shown if other props have them, and clicking selects also proposal w that prop id.
3. All prop id tags are shown in other tags (may get messy)