if ( resultCombo.isDisposed() || resultCombo == null ) return;
if ( resultCombo == null || resultCombo.isDisposed() ) return;
    public void update( Observable o, Object arg ) {    	if ( resultCombo.isDisposed() || resultCombo == null ) return;       	resultCombo.getDisplay().asyncExec( new Runnable() {                public void run() {                	if ( resultCombo.isDisposed() ) return;                    /* update the other text */                    if ( core.getNetworkInfoMap().getEnabledAndSearchable() == 0 ) {                        maxText.setEnabled( false );                        minText.setEnabled( false );                        resultCombo.setEnabled( false );                        extensionCombo.setEnabled( false );                    }                    else {                        maxText.setEnabled( true );                        minText.setEnabled( true );                        resultCombo.setEnabled( true );                        extensionCombo.setEnabled( true );                    }                }            } );        super.update( o, arg );    }