See about fixing gate smoothly, leaving no gaps (6)
I believe the answer is:
legato
'leaving no gaps' is the definition.
(musical term)
'see about fixing gate' is the wordplay.
'see' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'about' indicates putting letters inside.
'fixing' indicates anagramming the letters.
'gate' is an anagram of 'egat'.
'lo' going around 'egat' is 'LEGATO'.
'smoothly' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for legato that I've seen before include "Played smoothly" , "In a smooth and flowing manner (music)" , "Musically smooth" , "play on without pause" , "scored smoothly" .)