Loss of function of "Enter" key - big ergonomic step backward

It used to be possible to complete most functions simply by hitting the Enter key on my keyboard. Now many of the same functions require clicking the green check mark. I have to move the mouse to the check mark and click it, or else right-click to bring up a check mark and then click it.

Either way, this is a big step in the wrong direction ergonomically. Even though the mouse was invented at my workplace, I am no fan. Those of us suffering from RSI are now suffering more. Why was this change made? How is it possibly justified? How can I change it back?

This is SW2011 SP5.0.

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