Hello, Faithful Eli, 

The provided sample video was very helpful for illustrating the undesired behavior that you are facing. 

I would like to note that for all our text editors we are hosting the standard TextBox control. This means that whatever behavior you are experiencing with our editors, the same will be with the standard TextBox control. We also offer RadTextBoxControl which is an implementation of a text box built entirely with TPF. However RadTextBoxControl does not support features such as Right-To-Left and IME. We already have an existing feature request for this. You can track its progress, subscribe for status changes and add your comments on the following link: 

https://feedback.telerik.com/winforms/1368262-add-radtextboxcontrol-add-right-to-left-support 

That is why you are experiencing this problem with the cursor wen using RadTextBoxControl. 

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

I have also updated your Telerik points.

Currently, the possible solution that I can suggest is to use RadTextBox and specify its TextAlign property to Right. The cursor is properly navigated to the left most position.

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik