Based on discussion http://wpftoolkit.codeplex.com/discussions/447813#post1069463
DecimalUpDown seems to be ignoring MouseWheelActiveOnFocus property. The mousewheel is only active when the mouse pointer is on the control irrespective of this setting.
"MouseWheelActiveOnFocus" property is now obsolete, but the same problem occurs with "MouseWheelActiveTrigger" property :
When focus is on the DecimalUpDown (with MouseWheelActiveTrigger = Focused), and mouse pointer is outside the DecimalUpDown, using the mouseWheel does nothing. If the mouse pointer is over the DecimalUpDown, using the mouseWheel increments/decrements.
It looks like ButtonSpinner.OnMouseWheel() is only called when mouse is over the Control.
Comments: ** Comment from web user: BoucherS **
DecimalUpDown seems to be ignoring MouseWheelActiveOnFocus property. The mousewheel is only active when the mouse pointer is on the control irrespective of this setting.
"MouseWheelActiveOnFocus" property is now obsolete, but the same problem occurs with "MouseWheelActiveTrigger" property :
When focus is on the DecimalUpDown (with MouseWheelActiveTrigger = Focused), and mouse pointer is outside the DecimalUpDown, using the mouseWheel does nothing. If the mouse pointer is over the DecimalUpDown, using the mouseWheel increments/decrements.
It looks like ButtonSpinner.OnMouseWheel() is only called when mouse is over the Control.
Comments: ** Comment from web user: BoucherS **
In v2.3 of the toolkit, a fourth MouseWheelActiveTrigger will be available : "Focused".
When an UpDownControl has its MouseWheelActiveTrigger property set to "Focused" and the focus is on its TextBox, the mouse wheel will be registered, no matter where the mouse is (over or outside the UpDownControl).
So the increment/decrement will be done with the mouseWheel until another control is focused.