Make sure the MIDI Channel setting in Patch Base matches the Channel set on your Volca FM2.
The “Patch Seq Sync” setting will automatically send the current patch from the Voice editor to the Volca FM2 every time an edit is made in the Sequence editor; this is useful if you are creating a Voice patch that isn't yet saved to the Volca's memory. If this setting is turned off, then every time an edit is made in the Sequence editor, the Volca will switch to the saved Voice patch specified by the “Program” setting in the sequence.
Please note that the Volca FM2 only accepts full patch dumps, not individual parameter changes, which means that when you make a change in the editor, the full patch is sent to the Volca. This means that patch edits can feel a little slow (half a second delay or so), and that you will hear voice dropouts if you make an edit in the middle of the note. This is a limitation of the hardware.
Like the Patch Editor, Sequence edits require send a full dump to the Volca, so there is a small delay between when you make an edit and when you hear the result on the synth.
Use this window to fetch both the current Voice and Sequence from the Volca in a single click. Also, using this window you can save the current Voice and Sequence to a single file for later use, allowing you to create custom sequence/sound combinations without relying on the Volca FM2's internal memory.