I tried different ways to modify IntegerUpDown to get rounded edges.
Here are my observations:
IntegerUpDown -> CommonNumericUpDown -> NumericUpDown -> UpDownBase -> InputBase -> InputBase -> Control
NumericUpDown has a Style that indicates that the control consists of a ButtonSpinner x:Name="PART_Spinner" and a WatermarkTextBox x:Name="PART_TextBox"
(in the NumericUpDown class it is specified that [TemplatePart( Name = PART_TextBox, Type = typeof( TextBox ) )])
Everything is clear here
WatermarkTextBox -> AutoSelectTextBox -> TextBox
WatermarkTextBox also has its own Style and defines a new Template for it.
I've been trying to change different Templates in different places throughout the day, but I still can't get the result I want

I tried different ways to modify IntegerUpDown to get rounded edges.
Here are my observations:
IntegerUpDown -> CommonNumericUpDown -> NumericUpDown -> UpDownBase -> InputBase -> InputBase -> Control
NumericUpDown has a Style that indicates that the control consists of a ButtonSpinner x:Name="PART_Spinner" and a WatermarkTextBox x:Name="PART_TextBox"
(in the NumericUpDown class it is specified that [TemplatePart( Name = PART_TextBox, Type = typeof( TextBox ) )])
Everything is clear here
WatermarkTextBox -> AutoSelectTextBox -> TextBox

WatermarkTextBox also has its own Style and defines a new Template for it.
I've been trying to change different Templates in different places throughout the day, but I still can't get the result I want