Clarify name/variable interop.

Author: barnson

src/xsd4/thmutil.xsd

@@ -626,7 +626,7 @@
                     <xs:annotation>
                         <xs:documentation>
                             Initial text for the control.
-                            Mutually exclusive with the StringId attribute.
+                            Mutually exclusive with the StringId attribute and child Text elements.
                         </xs:documentation>
                     </xs:annotation>
                     <xs:attributeGroup ref="CommonControlAttributes" />
@@ -867,7 +867,7 @@
                             </xs:documentation>
                         </xs:annotation>
                     </xs:attribute>
-                </xs:extension>                
+                </xs:extension>
             </xs:simpleContent>
         </xs:complexType>
     </xs:element>
@@ -900,7 +900,7 @@
         <xs:annotation>
             <xs:documentation>
                 Defines a progress bar image.
-                The image must be 4 pixels wide: left pixel is the left side of progress bar, left middle pixel is progress used, right middle pixel is progress unused, right pixel is right side of progress bar. 
+                The image must be 4 pixels wide: left pixel is the left side of progress bar, left middle pixel is progress used, right middle pixel is progress unused, right pixel is right side of progress bar.
                 If multiple ProgressbarImages are given, each is assigned an index in document order and can be selected programmatically with ThemeSetProgressControlColor.
             </xs:documentation>
         </xs:annotation>
@@ -1068,7 +1068,7 @@
                             </xs:documentation>
                         </xs:annotation>
                     </xs:attribute>
-                </xs:extension>                
+                </xs:extension>
             </xs:simpleContent>
         </xs:complexType>
     </xs:element>
@@ -1207,7 +1207,24 @@
     <xs:attributeGroup name="CommonControlAttributes">
         <xs:attribute name="Name" type="xs:string">
             <xs:annotation>
-                <xs:documentation>Optional name for the control.</xs:documentation>
+                <xs:documentation>
+                    Optional name for the control.
+
+                    If the ThmUtil variable callback system has been configured, such as by
+                    WixStandardBootstrapperApplication, ThmUtil uses the control name to
+                    find a matching variable name. ThmUtil retrieves the variable's value
+                    to set the initial value of the control and sets the variable's value
+                    when the user interacts with the control.
+
+                    For example, a checkbox control is checked when the matching variable
+                    has a nonzero value and unchecked for a value of `0`. When the user
+                    checks a checkbox control, ThmUtil sets the variable value to a nonzero
+                    value (currently `1`) and to `0` if the checkbox is unchecked.
+
+                    An edit box control gets its initial value from a matching variable
+                    value. The control value is saved to the variable when navigating away
+                    from the page or when choosing a folder via an associated Browse button.
+                </xs:documentation>
             </xs:annotation>
         </xs:attribute>
         <xs:attribute name="EnableCondition" type="xs:string">