I assume you're talking Mopar half doors... If the weather stripping is not stay in, you are not getting it into the groove completely. Keep trying it will take a few times to get it right.
2013 JK Rubicon - Dualtops, Full and Half Doors | AEV 2.5" DualSport XT w/ Geo correction brackets | Teraflex Monster TrackBar | 315/70/17 Duratrac's on Fuel Anza wheels | Fox 2.0 ATS Stabilizer | more... & more...
2014 JK Sport - 100% Stock, for now