lib/Ext/SegmentedButton.js
function(button) {
        if (!this.getAllowToggle()) {
            return;
        }
        var me             = this,
            pressedButtons = me.getPressedButtons() || [],
            buttons        = [],
            alreadyPressed;

        if (!me.getDisabled() && !button.getDisabled()) {
            //if we allow for multiple pressed buttons, use the existing pressed buttons
            if (me.getAllowMultiple()) {
                buttons = pressedButtons.concat(buttons);
            }

            alreadyPressed = (buttons.indexOf(button) !== -1) || (pressedButtons.indexOf(button) !== -1);

            //if we allow for depressing buttons, and the new pressed button is currently pressed, remove it
            if (alreadyPressed && me.getAllowDepress()) {
                Ext.Array.remove(buttons, button);
            } else if (!alreadyPressed || !me.getAllowDepress()) {
                buttons.push(button);
            }

            me.setPressedButtons(buttons);
        }
    }
function(button) {
        if (!this.getAllowToggle()) {
            return;
        }
        var me             = this,
            pressedButtons = me.getPressedButtons() || [],
            buttons        = [],
            alreadyPressed;

        if (!me.getDisabled() && !button.getDisabled()) {
            //if we allow for multiple pressed buttons, use the existing pressed buttons
            if (me.getAllowMultiple()) {
                buttons = pressedButtons.concat(buttons);
            }

            alreadyPressed = (buttons.indexOf(button) !== -1) || (pressedButtons.indexOf(button) !== -1);

            //if we allow for depressing buttons, and the new pressed button is currently pressed, remove it
            if (alreadyPressed && me.getAllowDepress()) {
                Ext.Array.remove(buttons, button);
            } else if (!alreadyPressed || !me.getAllowDepress()) {
                buttons.push(button);
            }

            me.setPressedButtons(buttons);
        }
    }
Button sets a timeout of 10ms to remove the {@link #pressedCls} on the release event.
We don't want this to happen, so lets return `false` and cancel the event.
@private