I would like to disable some lines in the 'Select by expression' dialog (QGIS 2.6) but I can't find whether it is possible or not, and if yes, how to achieve that.
I have tried several characters such as /, //, /*, #, REM.
Note that /*
and REM
transform the line into green text, which seems to be disabled, but the query result is empty and I get in invalid expression error below the query field.