Bootstrap Clean Theme loses blocks when $THEME->layout side-pre and side-post are swapped

NOTE - you cannot test this bug until MDL-40065 is fixed, as you get an exception error

In theme Standard, if the user edits the $THEME->layout and changes from 'side-pre','side-post' to 'side-pre' OR 'side-post', the navigation, administration, and calendar blocks move to whichever side is visible.

In theme Clean (Bootstrap), this doesn't appear to be the case. The blocks can disappear.

How to test:

Turn on Debug to Developer and Theme Design Mode on

Copy the entire section of $THEME->layouts from bootstrapbase/config.php and paste into config.php of clean/config.php

Select Site Admininstration / Appearance / Theme / Theme Selector and select Clean theme. Go to the front page (ALL should be OK. By default, theme Clean has only 'side-pre'

Select "Turn Editing On", then select each block and change the settings to default of right side and also right side for this page. When I refreshed the page, the blocks were still there, but...

In config.php of theme standard, and theme clean (please alter both!), change the front page layout to:

// The site home page.
'frontpage' => array(
'file' => 'general_frontpage.php',
'regions' => array('side-post'),
'defaultregion' => 'side-post',
'options' => array('nonavbar'=>true),

Purge caches after saving the two config.php files

Go back to the front page, and side-post area appears and the blocks are there.

Select Site Admininstration / Appearance / Theme / Theme Selector and select Clean theme. Go to the front page (ALL should be OK)

Select Site Admininstration / Appearance / Theme / Theme Selector and select Standard theme. Go to the home page (ALL should be OK)

Re edit the two config.php $THEME->layout to:

// The site home page.
'frontpage' => array(
'file' => 'general_frontpage.php',
'regions' => array('side-pre'),
'defaultregion' => 'side-pre',
'options' => array('nonavbar'=>true),

Purge caches again

Go to front page - all is still OK

Select Site Admininstration / Appearance / Theme / Theme Selector and select Clean theme. Go to the front page

Note that the block area is there, but none of the blocks have been moved to side-pre.