To reproduce:
-dnd button
-try to set it's "Pref Height" to "-Infinity" -- there will be a warning message
-try to set "Min Height" to the same value commiting with Tab key-- value will be changed to "USE_PREF_SIZE"
-repeat previous step -- now value becomes "-Infinity"
-try to set "Pref Height" to "-Infinity" commiting with Tab key -- there's no message this time and value is "-Infinity"