When an OLS ist started with the gui and several independent variables are selected, my gretl gui removes all independent variables when I try to remove only the last variable in the list of independent variables. Selecting any variable of the list works as expected, removing only the selected variable except for the last of the list. One has to change the order i.e. move the last variable one up to remove it. (It can be quite disturbing if you forget that and set the lags again etc.)
I am using gretl 1.9.90 on Fedora x64 and time series variables.