because I found it in my search after "Editbox"
This seams to work pretty good:
Code:
<Backdrop name="$(parent)ThresholdAmountBG" tier="HIGH" inherits="ZO_SingleLineEditBackdrop_Keyboard">
<Dimensions x="100" />
<Anchor point="TOPLEFT" relativeTo="$(parent)ItemLink" relativePoint="BOTTOMLEFT" offsetY="10" />
<Controls>
<EditBox name="$(parent)ThresholdAmount" inherits="ZO_DefaultEditForBackdrop ZO_EditDefaultText" />
</Controls>
</Backdrop>