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

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.

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