How can I get Selenium Web Driver to wait for an element to be accessible, not just present?

I assume the events timeline goes like this:

1. there are no needed elements on page.
2. needed element appears, but is disabled:
   <input type="button" id="createFolderCreateBtn" disabled="disabled" />
3. needed element becomes enabled:
   <input type="button" id="createFolderCreateBtn" />

Currently you are searching for element by id, and you find one on step 2, which is earlier than you need. What you need to do, is to search it by xpath:

//input[@id="createFolderCreateBtn" and not(@disabled)]

Here's the difference:

from lxml import etree


html = """
<input type="button" id="createFolderCreateBtn" disabled="disabled" />
<input type="button" id="createFolderCreateBtn" />
"""

tree = etree.fromstring(html, parser=etree.HTMLParser())

tree.xpath('//input[@id="createFolderCreateBtn"]')
# returns both elements:
# [<Element input at 102a73680>, <Element input at 102a73578>]


tree.xpath('//input[@id="createFolderCreateBtn" and not(@disabled)]')
# returns single element:
# [<Element input at 102a73578>]

To wrap it up, here's your fixed code:

try:
    print "about to look for element"
    element_xpath = '//input[@id="createFolderCreateBtn" and not(@disabled)]'
    element = WebDriverWait(driver, 10).until(
            lambda driver : driver.find_element_by_xpath(element_xpath)
    )
    print "still looking?"
finally: 
    print 'yowp'

UPDATE:
Repasting the same with the actual webdriver.
Here's the example.html page code:

<input type="button" id="createFolderCreateBtn" disabled="disabled" />
<input type="button" id="createFolderCreateBtn" />

Here's the ipython session:

In [1]: from selenium.webdriver import Firefox

In [2]: browser = Firefox()

In [3]: browser.get('file:///tmp/example.html')

In [4]: browser.find_elements_by_xpath('//input[@id="createFolderCreateBtn"]')
Out[4]: 
[<selenium.webdriver.remote.webelement.WebElement at 0x103f75110>,
 <selenium.webdriver.remote.webelement.WebElement at 0x103f75150>]

In [5]: browser.find_elements_by_xpath('//input[@id="createFolderCreateBtn" and not(@disabled)]')
Out[5]: 
[<selenium.webdriver.remote.webelement.WebElement at 0x103f75290>]

UPDATE 2:

It works with this as well:

<input type="button" id="createFolderCreateBtn" disabled />

    print time.time()
    try:
        print "about to look for element"
        def find(driver):
            e = driver.find_element_by_id("createFolderCreateBtn")
            if (e.get_attribute("disabled")=='true'):
                return False
            return e
        element = WebDriverWait(driver, 10).until(find)
        print "still looking?"
    finally: print 'yowp'
    print "ok, left the loop"
    print time.time()

Here is what we ended up with. (Thanks to lukeis and RossPatterson.) Note that we had to find all the items by id and then filter by "disabled". I would have preferred a single search pattern, but what can you do?

I think something along these lines should work as well:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions

browser = webdriver.Firefox()
wait = WebDriverWait(browser, 30)
wait.until(expected_conditions.presence_of_element_located((By.XPATH, "//*[@id='createFolderCreateBrn' and not(@disabled)]")))