That " glue " is solvent .

it dissolves the plastic at the joint and creates a weld .

the solvent then evaporates completely leaving the new , solid connection .

It also dissolves the acrylic resin in the paint .

It will dissolve enamel paint also .

Those types of plastic cement are essentially the same formula as many airbrush cleaners .

Butyl acetate and acetone . Sometimes also butanone or ethyl acetate when it's the " fast setting " variety .

You can glue pre-painted parts in place but you need to use a smaller brush to apply a tiny amount of that solvent to only the point of contact .

Dab on a small amount of solvent to the tab of the part and then quickly install it .

that way you avoid flooding the joint with solvent .

If you don't have a  spare brush you can still use the bottle's brush -  just hit the lip of the bottle with the brush to knock off the majority of the solvent prior to touching it to the part to be attached .