As stated in the linked forum thread, the RadDock doesn't use the properties that configure the borders. In order to achieve the desired effect you should modify the styles of the control's skins. The example below will demonstrate another solution for removing the background of the borders on the markup of the page (you can move the used CSS styles in a stylesheet file if you wish):
This sample should be placed in the head section of the page:
.rdDisabled .rdMiddle .rdLeft,
.rdDisabled .rdMiddle .rdRight,
.rdDisabled .rdBottom .rdLeft,
.rdDisabled .rdBottom .rdCenter,
.rdDisabled .rdBottom .rdRight
By setting the CSS class rdDisabled in the property CssClass of the RadDock, you will apply the styles, defined above.
I hope that helps. Feel free to contact us again if you encounter more difficulties.
the Telerik team
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