duplicate buffers when selecting the same label again

[eMBee]

when selecting a label (with L) a new buffer is created, even if one for that label already exists.

the result is that i quickly accumulate dozens of buffers as i switch labels frequently and always use the label-list, since that tells me which label has new messages.

to avoid creating new buffers i could use the buffer list to switch, but that doesn't tell me if a buffer has updates.

btw: this same problem has existed for searches since i started using sup, but it is less disrupting there.