webdriver: can not check javascript variable when print dialog is open.

For example,

    JavascriptExecutor executor = (JavascriptExecutor)driver;
    return (Boolean) executor.executeScript("return jQuery.active == 0");

Before opening print dialog, its value is 0. But When print dialog is opened, from Chrome console, the jQuery.active always shown as empty(not accessible?). After closing the print dialog, its value is 0.

As a result, wait for jQuery.active==0 timeout if print dialog is opened before the wait.