Please note that providing links to dev version of our assemblies in the forums is unacceptable.
Now to your question - all RadInput textboxes have a number of <input type="text" /> elements, which are rendered, but hidden with CSS. These hidden textboxes are used for storing the control value in a different format, etc. The number of hidden textboxes is different, depending on the control. RadTextBox has only one, while numeric textboxes and masked textboxes have two. Since the hidden textboxes are positioned on the right side of the visible textbox, they push the visible textbox to the left when the controls are placed inside a right-aligned container.
You options are:
1) Use right margin of 1px for right-aligned RadTextBox controls
2) hide the invisible textboxes completely with a display:none style. This is an option if you are not using validator callout extenders, because they rely on these hidden textboxes in order to position the callouts.
display: none !important;
We will research for a way to prevent such unexpected behavior in the future.
the Telerik team