/// <summary>
        /// Updates the colour palette.
        /// </summary>
        /// <param name="useCircularPictureBoxes">if set to <c>true</c> [use circular picture boxes].</param>
        private void UpdateColourPalette(bool useCircularPictureBoxes)
        {
            if (useCircularPictureBoxes)
            {
                kgbPreviewPane.Visible = false;

                kgbCircularColourPreviewPane.Visible = true;

                ColourUtilities.GrabColourDefinitions(cbxBaseColourPreview, cbxDarkColourPreview, cbxMiddleColourPreview, cbxLightColourPreview, cbxLightestColourPreview, cbxBorderColourPreview, cbxAlternativeNormalTextColourPreview, cbxNormalTextColourPreview, cbxDisabledTextColourPreview, cbxFocusedTextColourPreview, cbxPressedTextColourPreview, cbxDisabledColourPreview, cbxLinkNormalColourPreview, cbxLinkFocusedColourPreview, cbxLinkHoverColourPreview, cbxLinkVisitedColourPreview, cbxCustomColourOnePreview, cbxCustomColourTwoPreview, cbxCustomColourThreePreview, cbxCustomColourFourPreview, cbxCustomColourFivePreview, cbxCustomTextColourOnePreview, cbxCustomTextColourTwoPreview, cbxCustomTextColourThreePreview, cbxCustomTextColourFourPreview, cbxCustomTextColourFivePreview, cbxMenuTextColourPreview, cbxStatusTextColourPreview, cbxRibbonTabTextColourPreview);
            }
            else
            {
                kgbPreviewPane.Visible = true;

                kgbCircularColourPreviewPane.Visible = false;

                ColourUtilities.GrabColourDefinitions(pbxBaseColour, pbxDarkColour, pbxMiddleColour, pbxLightColour, pbxLightestColour, pbxBorderColourPreview, pbxAlternativeNormalTextColour, pbxNormalTextColourPreview, pbxDisabledTextColourPreview, pbxFocusedTextColourPreview, pbxPressedTextColourPreview, pbxDisabledColourPreview, pbxLinkNormalColourPreview, pbxLinkFocusedColourPreview, pbxLinkHoverColourPreview, pbxLinkVisitedColourPreview, pbxCustomColourOnePreview, pbxCustomColourTwoPreview, pbxCustomColourThreePreview, pbxCustomColourFourPreview, pbxCustomColourFivePreview, pbxCustomTextColourOnePreview, pbxCustomTextColourTwoPreview, pbxCustomTextColourThreePreview, pbxCustomTextColourFourPreview, pbxCustomTextColourFivePreview, pbxMenuTextColourPreview, pbxStatusTextColourPreview, pbxRibbonTabTextColourPreview);
            }
        }