Confusing/misleading “Dust:” label in coin selection dialog #699

1. 
   theStack commented at 6:32 pm on January 19, 2023: contributor

   The coin selection dialog in bitcoin-qt has a label named “Dust:”:

   

   This is very confusing, since in contrast to all other labels, the displayed information (yes/no) has literally nothing to do with the selected coins. All that this label shows is whether at least one of the outputs qualify as dust, but the outputs are set in a different dialog. And even worse, the dust check is currently simply wrong because it only looks at an output’s nValue and just assumes a P2PKH script size:

   https://github.com/bitcoin/bitcoin/blob/250598a905a7be74d4064495c22e2423e371fe8a/src/qt/coincontroldialog.cpp#L400-L402

   My suggestion would be to simply remove it, but wanted to first discuss this here before opening a PR. Was the original intention maybe to apply the dust check to the inputs? (I.e. “Is any of the selected inputs dust?”). Does anyone find this shown information useful?

2. 
   john-moffett commented at 3:06 pm on January 20, 2023: contributor

   I think the intent was that the user would first set the send value(s) then select which coin(s) to use. If your coin choices end up requiring a change output smaller than the dust amount, it’ll let you know:

   It’s grayed out because you haven’t set any target output amounts. I guess a better (but overly verbose) label would be: “Might this end up creating any dust outputs: "

   I messed around for a minute or two trying to get it to turn red for the change output but with no success. Maybe due to discard_rate effects? Only when the manually-specified output value was below the threshold did it turn red and say “yes”. But that shouldn’t have anything to do with coin selection.

   At this point, I’m inclined to agree that it should be removed for now.

3. 
   furszy commented at 3:44 pm on January 20, 2023: member

   So, the dust label inside the coin control dialog corresponds to the user setting or not a recipient in the send screen with a value lower than the dust amount? That is quite messed up.

   ACK on removing it.

4. 
   hernanmarino commented at 7:35 pm on March 13, 2023: contributor

   +1 on removing it
5. hebasto closed this on Jul 4, 2023

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6. timemarkovqtum referenced this in commit 7446cb186c on Jan 30, 2024
7. bitcoin-core locked this on Jul 3, 2024

Contributors
theStack john-moffett furszy hernanmarino