Pillifying removes character before Pill

[t3chguy]

so (Travis [TAB] results in Pill but ( goes away :(

[lukebarnard1]

This seems unique to \S characters, that is characters that are not considered whitespace. And this only happens when tab completing, so

if (force && this.shouldForceComplete()) {
        commandRegex = /\S+/g;
}

is looking suspect.

This means that when tab-completing, the regex changes from @\S* to \S+ for the UserProvider (the thing providing user completions). \S+ will go and match anything before the display name entered that isn't whitespace.

This is a side-effect of tab-completing free-form text to free-form, arbitrary display names.

[ara4n]

fixed in matrix-org/matrix-react-sdk#1890