Parameter HTML form issues

[lutsik]

• Selectors w/o default values need to be interacted with to set a value (tested on Safari, Firefox). Although it is understandable why, for usability one can pass just the first value in the list
• For text fields "Please fill in..." text is set in case no value is specified, turn it into a background tooltip
• [hard to reproduce] sometimes the validation just results in "An unknown error occurred" without an obvious reason with "index out of range" errors in the server-side log