Property name: Required

Property name: Required
Question types applied	All except Page question
Description	Specifies whether or not a question is required. This property exists only for question properties.
Business logic	When the 'All required' property of a questionnaire is checked all questions in a questionnaire will be required as default. The required property on a question can although overrule the 'All required' property of the questionnaire. If there is no value for this property in a question, its value will be inherited from the questionnaire property. You will be able to see what the inherited value is since the Yes or No property will be illustrated as a black box instead of white. You can click the black box as well if you want to ensure that the value is always a certain value event though the default questionnaire property may be changed.
Formatting	Yes / No For grid questions, this property also has text box below to enter the range indices of sub-questions which will be required. Only the sub questions in the specified range will be required. A range is written in a format like [1-3], [1,4-7], [1,3,5], etc.
Screen examples	The image below shows this property in the question properties dialog. The black boxes indicates that the current inherited value is Yes.