Hello Suresh,

Thank you for the additionally provided information. Now, I understand that the transparent BackColor of the RadCheckedDropDownList is your requirement. In this case, I can suggest to set the UseCompatibleTextRendering property of the TokenizedTextBlockElement to true. You can do this  in the TextBlockFormatting event where you have already been subscribed:

private void radCheckedDropDownList1_TextBlockFormatting(object sender, Telerik.WinControls.UI.TextBlockFormattingEventArgs e)
        {
            TokenizedTextBlockElement token = e.TextBlock as TokenizedTextBlockElement;
            if (token != null)
            {
                token.ContentElement.UseCompatibleTextRendering = true;
            }
        }

However, I would like to note that Windows Forms controls do not support true transparency. The background of a transparent Windows Forms control is painted by its parent. Even when you set the BackColor of control to Transparent you're not making the control "see-through". You're actually telling the control to take on the background properties of its parent container. The following threads will be useful on this topic:
https://stackoverflow.com/questions/4387680/transparent-background-on-winforms

https://docs.microsoft.com/en-us/dotnet/framework/winforms/controls/how-to-give-your-control-a-transparent-background

I hope this information helps. Should you have further questions please let me know.

Regards,
Nadya
Progress Telerik

Hello Suresh,

Thank you for the provided project. 

After investigating it, I noticed that in the Designer.cs file the BackColor of RadCheckedDropDownList is set to transparent. When I commented on this line it seems to work correctly now. Below is the result on my end:

I attached the updated to this thread as well. 

I hope this helps. Let me know if you need further assistance.

Regards,
Nadya
Progress Telerik

Hello Suresh,

In the TelerikMetroBlue theme, FillPrimitive is responsible for setting colors in different states of the button. Note, that when the RadCheckDropDownList is expanded the button is blue, when it is collapsed the button color becomes transparent and receive the color from its parent. Please see the attached gif file.

I attached my sample project to this thread. Could you please refer to it and see how it works.

I hope this information helps. If you have other questions do not hesitate to ask.

Regards,
Nadya
Progress Telerik

Hello Suresh,

I was able to replicate the problem when the TelerikMetroBlue theme is applied. 

I have logged it in our feedback portal by making this thread public on your behalf. You can track its progress, subscribe for status changes, and add your comments on the following link - feedback item.

As a reward, I updated your Telerik Points.

To workaround this issue you can set ArrowButton.ShouldPaint property to true:

this.radCheckedDropDownList1.DropDownListElement.ArrowButton.ShouldPaint = true;

The achieved result is demonstrated in the attached gif file.

I hope this helps. Should you have other questions do not hesitate to ask.

Nadya
Progress Telerik