UI/UX Trap: Single-pair filter edits silently pollute the Global Filter for future pairs

[Rafalus]

Hi,

I ran into an unintuitive UI trap regarding how FreeFileSync handles filters when starting with a single folder pair versus adding multiple pairs later.

The Problem:
When you have only a single folder pair configured in the main window:
1. There are no per-row filter/funnel icons between the paths; there is only the top toolbar filter button.
2. Opening the filter settings dialogue displays no "Folder pair" sidebar on the left.
3. Because of this, editing the filter feels like editing the rule specifically for that single visible folder pair. In reality, it modifies the global <Filter> configuration.

S10.jpg

The Trap:
If you configure a specific include filter for that initial folder pair (for example, isolating a single file: `\GEMINI.md`) and subsequently click the green "+" button to add a second folder pair (such as a subfolder to sync entirely), the newly added pair defaults to inheriting the global filter.

S20.jpeg

Because the user assumed they were setting a pair-specific filter earlier, the global filter is now locked to `\GEMINI.md`. As a result:
- The second folder pair inherits this filter silently.
- The comparison for the second pair fails or scans 0 files.
- Only after multiple rows exist does the "Folder pair" selection sidebar appear inside the settings window to reveal that "All folder pairs" was the scope being edited all along.

Suggestion:
It would prevent substantial troubleshooting confusion if:
1. Even when only one folder pair exists, the per-row filter/funnel icons between the paths and the "Folder pair" sidebar in the Filter/Settings dialogue remain visible, clearly distinguishing between "All folder pairs (Global)" and the specific pair.
OR
2. Editing the settings when only one pair exists defaults to creating a pair-specific rule rather than overriding the global template for all future rows.