how did this happened

okay i was playing today and i saw that my shotgun was equipped in the secondary slot
is this a glitch or something cuz i got to use it in game and i have no idead how dis happened
here is the screeni

hm , never seen anything like that lol, not really a problem is it?

no, its better LOL, pistols suck against shotties Can you play pistols only with it? xp