Clears the item at the given zero-relative index in the receiver.
The text, icon and other attributes of the item are set to the default
value. If the tree was created with the <code>SWT.VIRTUAL</code> style,
these attributes are requested again as needed.
@param index the index of the item to clear
@param all <code>true</code> if all child items of the indexed item should be
cleared recursively, and <code>false</code> otherwise
@exception IllegalArgumentException <ul>
<li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li>
</ul>
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
</ul>
Clears the item at the given zero-relative index in the receiver. The text, icon and other attributes of the item are set to the default value. If the tree was created with the <code>SWT.VIRTUAL</code> style, these attributes are requested again as needed.
@param index the index of the item to clear @param all <code>true</code> if all child items of the indexed item should be cleared recursively, and <code>false</code> otherwise
@exception IllegalArgumentException <ul> <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li> </ul> @exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> </ul>
@see SWT#VIRTUAL @see SWT#SetData
@since 3.2