I know this is the most unpopular feature of the S5 phone, but still, it only breaks if you don't take care of it.
I have two S5 phones, one since release day (mine) and the OEM charger cover is still as good now as it was when I got them.
I only use my left hand, little pinky fingernail to open it. Once it is open, you don't just swing it to the right, you must "tug it out" just a tiny bit to get the smallest (narrowest) part of the tag line. There is a very definitely "feel" to when it is out all the way.
Then never, ever try to swing it more than 90 degrees, or perpendicular to the end of the phone.
Putting it back, is a technique also. Tug it lightly to the left (phone face up to you) to about 45 degrees, and then push in lightly. That tail will retract back in, and then slide your thumbnail to the left. IF you insist on pushing in on the Left Side First, you are going to break it, the tail has not retracted all the way.
Has worked like a charm and no indication it is going to break.
Don't bother posting about IT SHOULD NOT BE THIS WAY.
You can't change what it is, learn to live with it, or just take it off and Get A Life...
Every other phone that I have owned, the charging port cover has broken on it. And none of those claimed to be Water Resistant. To make it Water Resistant means it must fit snug.
My 4 year old Galaxy S never had a charging port cover and it still works just fine. In fact, I just reactivated it today and added a new line for a Niece who's viral ex-husband just up and turned her phone off w/o even bothering to tell her. And she has to have a phone because she is on 24 hour call with Health Services.... If he were a 1,000 miles closer, I would go over and beat his sorry rump into the ground.