This is a workaround in order to ensure the field stays operational
for SiteTree and File records with the new $showSearch=true default.
Previously it was necessary to use setSearchCallback(), otherwise
the SQL query would fail. One limitation to keep this change generic
is that "MenuTitle" won't be used to search, since its SiteTree specific,
while the "Title" and "Name" fields are generally regarded as
model conventions (e.g. they're used in DataObject->getTitle() as well).
See https://github.com/silverstripe/silverstripe-framework/pull/2364
Set search option true on treedropdown fields by default, to provide a
fallback solution when trees fail to render (too many children errors)
Provide better indication/more meaningful styling to search (match
chosen styles for consistency)
In IE8, when a page in the preview iframe uses a web font (not just
references it in CSS, but actually has glyphs present in the page),
the fonts in the containing admin interface will become corrupted
(display as all squares) until the mouse moves.
This commit uses the technique described at
http://stackoverflow.com/questions/9809351/ie8-css-font-face-fonts-only-working-for-before-content-on-over-and-sometimes#10557782
to cause the admin panel to re-calculated all it's fonts
after the preview iframe has loaded, fixing the glitch
If multiple image manipulations are performend the resulting cached image is stored in assets/_resampled because the cached version of the image has no ParentID, which cacheFilename needs to set the correct path.
Currently IE6-8 will refuse to download files over HTTPS with default
Framework settings.
Currently the HTTP::add_cache_headers competely overrides Cache-Control
headers on each request, so there is no way to inject custom headers
from the API-consuning methods.
Also of note: adding no-store header also fixes the issue but will
prevent proxies from caching the request body (which they do when using
no-cache). So the setting max-age to some low number is a better choice
here.
This is needed in some situations when we only want to update a
small single component, sometimes even using a different controller to
the one implied in the URL.
An example here is reloading dynamically the subsite dropdown without
reloading the entire page, updating a filter sidebar or suchlike.
Updating the iframe src when the iframe isnt visible in IE8 causes a
view disconcerting font glitch (and it slows down navigation anyway),
so if the iframe isnt visible, delay setting the src until it is
