On the hp 30b, one can press the left pointing arrow to show all digits of a calculation. All digits remain displayed until clear is pressed. On the DM 42, show results in all 30+ digits are briefly displayed unless the show button remains pressed down. Is there any way to set it up where it behaves like the 30b where it can display all 30+ digits until one presses another button?
Short answer - no, there is no display mode to always see all the available digits on the DM42 (or any other Free42 platform), because doing that takes more than 1-line to see them, so it would block other stack levels.
Update: Sorry, I initially read your question wrong, I thought you wanted to have the full display stay on even after other keys. But the answer is the same, and the reason is basically because this is what the HP-42S does.