If a QTableWidget (Item-based) is added to a UI dialog, and its verticalHeaderDefaultSectionSize is set to a value smaller than 32 (e.g. 16), after saving and restarting QT Creator and loading the UI file, verticalHeaderDefaultSectionSize is reset to 32.

Step-by-step instructions:

• Start QT Creator
• File -> New File or Project -> Qt -> QT Designer Form -> Accept everything
• Drag a Table Widget from the Widget Box onto the Dialog
• Change "verticalHeaderMinimumSectionSize" to 16
• Change "verticalHeaderDefaultSectionSize" to 16
• Save
• Exit
• Start Qt Creator
• Open file via "File -> Recent Files"
• "verticalHeaderDefaultSectionSize" is again 32

Possible problem:

Probably the attributes "verticalHeaderDefaultSectionSize" and "verticalHeaderMinimumSectionSize" are loaded in the wrong order, causing the default "verticalHeaderMinimumSectionSize" to constrain "verticalHeaderDefaultSectionSize" to a value larger than 32.