Currently it is not possible to set an alpha value for a color in the RadColorPicker. It could be useful to add such a feature in the control.

The color picker doesn't looks good when zooming in the browser.

Try zooming to 120% and run your demo:

http://demos.telerik.com/aspnet-ajax/colorpicker/examples/overview/defaultcs.aspx

You need to reload the page after zooming!

The Web colors wraps, and the HSB/HSV tabs also wraps a lot!

Also see this thread:
http://www.telerik.com/forums/looks-really-bad-when-zooming

There are missing keys in the resx files and the resource files are not applied correctly. More info here: 

• https://www.telerik.com/forums/localizing-radcolorpicker-using-resource-files

This will allow the developer to disable postbacks, set the color with JavaScript on the client alone (or let the end user set it in preview mode), while postbacks are generally enabled (i.e. the server ColorChanged event will be fired only when the Apply button from the RGB palette is clicked or after the developer restores the AutoPostBack to true).

Setting RenderMode=Native doesn't work correctly in IE11.

Currently when the ShowIcon property of RadColorPicker is set to true and the controls does not have a selected color, a white color is displayed in the icon button. The expected behavior in this case would be to indicate that no color is selected, perhaps by displaying an image, similar to the one in the No Color button.

Put a color picker in each row of a RadGrid control with AllowRowsDragDrop=true. After choosing a color from the color picker, move the mouse. The result is that the grid row is dragged along with the mouse move.

Possible workarounds:

-set display: inline-block to the control wrapper -.RadColorPicker {display: inline-block;}

- use Classic RenderMode

- improve the z-index and backgrounds of the anchor:

		div.RadColorPicker.lwr div.rcpIcon a,
		div.RadColorPicker.lwr div.rcpIcon a:hover
		{
			z-index: 11;
			background-color: transparent;
			background-image: none;
		}

where the lwr class is to be added from the server code to avoid breaking the Classic render mode:

	protected void Page_Load(object sender, EventArgs e)
	{
		if (RadColorPicker1.RenderMode == Telerik.Web.UI.RenderMode.Lightweight)
		{
			RadColorPicker1.CssClass = "lwr";
		}
	}

When a Lightweight RadColorPicker has ShowIcon="true" and KeepInScreenBounds="true" configured, its tabs will be partially visible on the page.

The following solution can be used:

        <script>
            Telerik.Web.UI.ColorPicker.LightweightRenderer.prototype.getPaletteHeight = function ($palette) {
                var paletteHeight = $palette.height() +
                    $palette.find(".rcpTabs").height();
                return paletteHeight;
            }
        </script>

When the set_keepInScreenBounds method is called and you pass a true parameter, the popup of RadColorPicker is only partially visible (the tabs are hidden). 

When a RadColorPicker that only has the HSB or HSV palette is made visible or added during an AJAX request, it throws the following error:

Sys.ArgumentOutOfRangeException: Height should be an integer bigger than 1

This is caused by the lack of dimensions while the component is initializing on the client side and, for example, RGBSliders, manages to initialize correctly. The control must either have default dimensions for all modes, or to perform check for undefined dimensions provided by the browser, or both.

A workaround is to add the RGBSliders mode as the first mode so the control can initialize, and use a small JS handler that will switch to the HSB/HSV mode and hide the RGB mode.

Here follows an example that includes the workaround:

When the page is in RTL mode a color picker with a picker button shows it's popup the first time it is clicked but on the 2nd time you try to show the color picker palette it is not shown.

The simplest demo is here

https://demos.telerik.com/aspnet-ajax/imageeditor/examples/righttoleft/defaultcs.aspx 

 

To repro: go to add text, open the color popup, select a color then try to open the color popup again.

ColorPicker Causes unwanted scrollbar in page if It is used in a RTL page.
It's because of setting palleteWrapper.style.left to -9999px in hidePalette function in RadColorPicker.js.
It can be fixed if you set palleteWrapper.style.left to something like 0 or 50%. It will be out of page due to -9999px as top value anyway.

RadColorPicker remains clickable when its set_enabled(false) method is called.

Steps to reproduce:
1. Run this code:

        <telerik:RadColorPicker ID="RadColorPicker1" runat="server" ShowIcon="true" ShowEmptyColor="false" RenderMode="Lightweight" />
        <br /><br /><br />
        <select id="mySelect" onchange="EnableDisableColorPicker()">
            <option value="1">1</option>
            <option value="2" selected="selected">2</option>

        </select>
        <script>
            function EnableDisableColorPicker() {
                var x = document.getElementById("mySelect").value;
                var colorPicker = $find("<%= RadColorPicker1.ClientID %>");
                if (x == 1) {
                    colorPicker.set_enabled(false);

                } else {
                    colorPicker.set_enabled(true);

                }
            }
        </script>

2. Select option 1.

Result: RadColorPicker gets disabled, but remains clickable