For convenience I am pasting the reply I sent in your support ticket on the same subject - I believe it could be of help for other users as well:
This could happen in some scenarios because of the way RadFormDecorator styles checkboxes. When RadFormDecorator is used, the real checkboxes are hidden outside of the viewport. When the decorated checkbox is clicked however, browsers try to focus the real checkbox, hence the "jumping". To avoid that, the only thing that you usually need to do is to set position:relative
to the parent container. By "parent container" I mean the parent element that is wrapping the checkboxes - it could be a DIV or a SPAN tag for example.
In your case however, because of the RTL mode, the approach is a bit different. You need to add the following CSS in your page:
I hope this helps.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items