1fe9841a_on_Manager___LimeSurvey_Manual__Meaning
[Color] red-boxed text [Sample] a bold red line surrounds the error [Tooltip] description of the error [Comments] Any detected syntax errors are shown by surrounding the error with a red box. The tooltip shows the error. Examples include unmatched parentheses, use of undefined functions, passing the wrong number of arguments to functions, poorly structured expressions (e.g. missing operators between variables), trying to assign a new value to a read-only variable, trying to assign values to non-variables, or using unsupported syntax. Note that the syntax error dectection system may only report one error in an expression even if there are multiple errors; however, if any errors are detected, at least one error will be shown. [Meaning] 
syntax error
Expression Manager - LimeSurvey Manual
Meaning