EMB-145 First Officer reported after coordination with the ramp crew; the chocks were removed resulting in the aircraft moving forward 1 to 2 feet before the flight crew stopped the aircraft.

Narrative

Upon getting to push back from gate; all checklist were completed. Chocks were asked to be removed; I gave the go ahead making sure parking brake was set. Once the chocks were pulled; a few seconds later aircraft began to move; I reconfirmed with ground crew that parking was set using hand signals as the interphone was not connected at this point; both First Officer (FO) and I applied toe brakes coming to a full stop after rolling forward about 1-2 ft according to ground crew. After a complete stop they chocked the wheels. Ground manager was called; while I contacted Maintenance via phone. Explained what happened to Maintenance and said happened previously looking at the history. He talked to through turning the hydraulics on to keep pressure with the parking brake and it held with electric pumps to ON position. And gave me the okay to proceed. The ground crew manager connected interphone and I made sure everyone and everything was good with the crew and equipment. I explained that parking brake was set during the whole process and that I spoke to Maintenance and completed the procedure to ensure this wouldn't happen again. Manager understood and after conferring with the ground crew they were comfortable setting up for the pushback again. No damage was reported to us and the thug was never connected. The pushback was uneventful and we headed off to ZZZ1.