I am not able to reproduce the issue you have described with the moving handles in opposite direction. Could you reproduce it in our demo
site? We'll need your markup in order to reproduce the issue and assist further.
Regarding the second case if the start and end drag have the same value, not to be able to slide you could count on the client-side events to stop the value changing if the values are the same. Here's a demo showing the availbable events
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