Hello all, I'm currently trying to define a pair of integer parameters for min/max values: <param name="min_size" type="integer" optional="true" min="0" value="" label="Minimum" help="Optional, but if used you must also supply a maximum value." /> <param name="max_size" type="integer" optional="true" min="0" value="" label="Maximum" help="Optional, but if used you must also supply a minimum value." /> As far as I can tell from the documentation, there is no way to write a validator which links the two parameters, for example in order to insist that min_size <= max_size? http://wiki.galaxyproject.org/Admin/Tools/ToolConfigSyntax Alternatively, is it possible in the Cheetah section to raise an exception? That way at least the error should happen almost immediately (without having to wait for the cluster queue etc), e.g. raise ValueError("Requires minimum size is less than maximum!") Or, perhaps this particular use-case is common enough to warrant a new param type="integer-range" which shows two text boxes? Thanks, Peter