Hello Allin,
This is not actually a bug but may be you'll find it useful to point out.
I'm currenty handling a large census database and:
1. I observed some limitations through the GUI:
         a. adding new observations is limited to 100 00 obs;
         b. creating a new data set is limited to 1 000 000 obs;
         Otherwise, there's no limits to the "addobs" and
"nulldata" 
commands in the CLI
2. Plotting the frequency distribution of a constant series X (GUI) pops 
up a very clear error message " 'X' is a constant". Instead, the
"freq" 
command (CLI) ends up with 3 different error messages not so easy to 
figure out.
In the same run, the boxplot command has the same behavior (GUI-CLI) 
although the error message should perhaps, be more intuitive (like 
frequency's "'X' is a constant" for example instead of
"C:\Program 
Files\gretl\wgnuplot.exe" 
"C:\Users\Artur\AppData\Roaming\gretl\gpttmp.i03604": exit code 1").
3. While executing commands in the CLI - specially loop iterations - 
gretl seems to shut down but actually it doesn't.
Would be possible to show something like a progress bar (in fact, we 
used to have a stuff like that in the script window) just to tell the 
user that something is still going on?
Cheers,
artur