Autocomplete does not remove first character typed

If you autocomplete '$' everything's fine.
However if you autocompelte '$ser' then $services is the only possibility and this is properly detected. However the word 'services' is added after '$ser' resulting in '$serservices'.

The api is also in cause here, as it's the autocomplete rest api which should tell how many characters to remove before inserting the word. I'm also impacted in XEclipse when I try to implement auto complete calling the server side. I'm missing a number of chars to remove in the HintData structure.