I have OTR and MTM jackets which seem to suffer varying degrees of "lapel gape" or "popping", more prominent on the unstructured ones. Pretty sure the jackets aren't too tight, and suspect the problem having something to do with my posture / shoulders or incompatible shape of the armhole. Tailors have told me this can't be altered, but I've read online some had success trying to fix it, but nothing definitive. The cutter and tailor forum talks about lapel dart and tightening the bridle, but too technical for me and probably a fix for jackets still in the making stage. I'm thinking technically it can be solved, but no tailor is willing to do that for you. If so, what does it involve? Hope to find some answers here.