In particular, this commit actually renders the new custom_php.inc content type plugin useful...up until this commit, it only had 'Unknown contexts' being loaded into it.

#267545 by sun: Fix to layout form's js and radio select widgets; now works with IE and uses the preferable clear-block for formatting.

#258383 by gordon: Expands context to allow for more granular information about contextual data during various stages of the editing process (e.g.: not just that there's a node context, but what node TYPES are available in that context).

Renamed panels_get_directories() to panels_get_include_directories() to be more precise and descriptive.

Removed the pretty unhelpful panels_content grouping.
Fixed the docblock for panels_context_get_keywords() that was borking doxygen and causing nothing after it to be documented.
Updated the mainapi api docs grouping as needed.
Added the HookInvocations api docs grouping as appropriate.

Critical fix to plugin handling: client modules adding certain plugin types via the panels_include_directory() method were only half functioning.

Due to a foolish way of handling the module name in the first-round implementation of panels_include_directory(), module name information was not being properly recorded in plugins that needed it (layout plugins, esp.). The method of handling module name strings has been changed to resolve this problem.

The editor render callback property allows a content type to define the way it should be rendered in the display editor itself. This is useful if there are circumstances in which you really _do_ need to have the content preview displayed (which, as of beta4, is disabled).

#265908 by Pancho: Reduce the number of icons on the context order arranging page. Use newer icons in place of older ones.

#268480 by smk-ka: Fix to make sure that cached panes still get acted on by hook_panels_pane_content_alter().

#256461: Allow individual panel pane styles. This requires a small modification to existing panel styles so that panel styles don't conflict with pane styles, but it is very minor, and very few panel styles are out there yet.

#270363 by dww: Fixed problem with pane title rendering in the content editor (ternary was backwards).

Also improved readability and added explanatory comment.

Adds checks at various stages to ensure that $pane->shown is set; if it is not, then it defaults to TRUE, instead of FALSE (and therefore hidden).

Updated three content_type plugin properties: "ignore roles" is now "role-based access"; expanded the variables passed to "form control" and "visibility submit" callbacks.

Updated variable names in panels_add_content() to reflect the actual sort of data they're holding - basically, variable naming consistency. Also updated a few explanatory comments.

#262687 by JBrauer. Proper way of handling base_path() for icon images on display content editor, not just a hacky added slash at the base.

#260221 by sun, Pancho. Primarily codestyle cleanup; also fixed some missing leading slashes that were causing the edit icons not to appear in the new helptext for the display editor.

Small fix to get rid of array_intersect_keys(), which was implemented in PHP5.1.0 and therefore screws PHP4 compatibility.

Expanded standard helptext on the display editor to include explanations of the various buttons present in the editor.

Mostly changes to get rid of the big, ugly "Content preview has been disabled" message on panes, and stick that into a less-intrusive body message. Also some code legibility cleanup on calls to panels_ajax_form().

#261797 by Pancho. E_ALL fixes: ensuring that vars are declared as new stdClass() before being used as classless objects. Also some scattered bugfixes here and there.

#258483 by Pancho. No need to declare a var for a subset of $form_values that only gets used once. On the other hand, declaring that var in the validate function won't make it available in the submit function...! Fixed both the validate and submit handlers to use $form_values directly, nice and clean.

Changed show/hide settings to be more in line with the rest of the access control parameters. Part and parcel of that was moving storage of the pane show/hide information into the pane table itself...probably where it should have been from the start.

First round of work & debugging on hide/show panes is complete. In addition to the new js, php callback processor for the show/hide function, and small css changes to make hidden panes stand out as hidden, some residual cleanup from the big api rewrite. Also fixed a bug that was causing the configure form not to work for existing panes. Not sure why, the code SHOULD have worked fine, but...