Selenium / Firefox: Command “.click()” doesn't work with a found element

Question

I tried to find a solution to this thing and I spent a lot of time, but it is almost imposible to me to do that.

The matter: I am using Selenium with Java in Firefox

Answer 1

Finally I found an answer that works with Firefox as well as Google Chrome.

WebElement we = this.driver.findElement(By.id("size-btn"));

JavascriptExecutor executor = (JavascriptExecutor) driver;
executor.executeScript("arguments[0].click();", we);

waitForElementPresent(By.xpath("//div[@id='size-btn' and contains(@class,'opened')]/span"));

Thanks for reading me.