Control console mulfanction on Craftsman 3/4 HP chain garage opener

Just installed new 3/4 Craftsman chain garage opener. Problem: system operates correctly only without main big push bar on the wall mounted control console (they call it "Motion Detecting Control Console". That push bar plays a role of a close-open button (by pushing tiny inside knob). It also has green light which is up with system power up. After I installed that console, I did not see a green light. I pushed the push bar several times, without any result: no door movement. But after I tried to open the console (remove the push bar) green light turned on and door went down, and then immediately went up. I removed that push bar and find out that by pushing tiny blue button I can properly close and open the garage. I installed bar back. Green light was up and I could have closed and opened the door properly. Then suddenly door opened by itself and green light turned off.
Now I removed that "push bar" and open and close the garage by pushing that blue tiny button.
I have three questions:
1. Did anybody get problem like that.
2. I suspect that cover (push bar) made wrong (may be plastic warped), so what can I do to fix it.
3. What if I replace that control console with simple door-bell push button? I do not have keyless entry system, I do not need motion detection to turn on garage lights. Will simple button open and close garage door?
Thanks for answers.
Alex