Text input enlarges movie clip too much?

programming flash
1

in CS4:

public class TestComponent extends MovieClip{
var textInput:TextInput = new TextInput();

    function TestComponent():void{
        trace('textInput W x H: ' + textInput.width + 'x' + textInput.height);
        trace('clip W x H: ' + width + 'x' + height);
        
        addChild(textInput);
        
        trace('textInput W x H: ' + textInput.width + 'x' + textInput.height);
        trace('clip W x H: ' + width + 'x' + height);
    }
}

output:
textInput W x H: 100x22
clip W x H: 0x0
textInput W x H: 100x22
clip W x H: 100x100

This is bizarre to me.
Does anyone know why the height has become 100 instead of 22, like the textInput. Right now I just have to store the height before adding stuff to it since components seem to “corrupt” it.