Selections are reset after cancel in columns dialog

Fix #626 
Not sure if this is a correct way of doing it but it's working. (tested on openmrs)
Signed-off-by: Sheik Hassan <solergiga@yahoo.com>
The reason this delay was added to originally was because resetting the selection would cause the dialog to block briefly due to the overhead of resetting. This overhead may no longer be an issue, but it should not be the cause for why the columns aren't being properly reset.