I'm aware of the PSE bug in the current 15c LE firmware, but I'm wondering if the following issue is also present in the original 15c:
As written on page 144 in the manual, if you store/reclall a value on a matrix you can just hold the button "about 3 seconds" to cancel assignment - the calculator will display "null".
Now it looks like on my 15c LE this is rather 2 seconds or even less - also in general if the calculator does show status messages (e.g. The current row/column in matrix entering mode) they are shown so short and quickly I have hard time reading them. Is this also the same on the original 15c?