Add option to select only leaves

[v4ssi404]

Scope

This pull request includes a

• [ ] Bug fix
• [x] New feature
• [ ] Translation

Changes

The following changes were made (this change is also documented in the change log):

• New boolean property restrictSelectToLeaves to restrict nodes selection to leaves on TreeViewInput.

Related Issues

If this is related to an existing ticket, include a link to it as well.

[kartik-v]

Go through the documentation for the Tree Node model methods.

You can achieve this by overriding the isDisabled method in your Tree node model as described here.

/**
 * Override isDisabled method if you need as shown in the  
 * example below. You can override similarly other methods
 * like isActive, isMovable etc.
 */
public function isDisabled()
{
    return $this->children()->count() > 0; // this will disable parent selection
}