Marcel Taeumel uploaded a new version of System to project The Trunk:
http://source.squeak.org/trunk/System-mt.830.mcz

==================== Summary ====================

Name: System-mt.830
Author: mt
Time: 17 May 2016, 2:24:39.256089 pm
UUID: 7cf55fb7-9e1f-5c45-baf8-eb29fcf2ac91
Ancestors: System-mt.829

Fixes a bug where space was reserved for flaps when positioning windows although no flaps were visible at all.

Now, the preference #fullScreenLeavesDeskMargins works as expected.

=============== Diff against System-mt.829 ===============

Item was changed:
  ----- Method: RealEstateAgent class>>maximumUsableAreaInWorld: (in category 'accessing') -----
  maximumUsableAreaInWorld: aWorldOrNil
  
  	| allowedArea |
  	allowedArea := Display usableArea.
  	aWorldOrNil ifNotNil: [
  		allowedArea := allowedArea intersect: aWorldOrNil visibleClearArea.
+ 		Smalltalk isMorphic ifTrue: [
+ 			(((Smalltalk classNamed: 'Flaps') ifNil: [false] ifNotNil: [:cls | cls anyFlapsVisibleIn: aWorldOrNil])
+ 				and: [self respondsTo: #reduceByFlaps:])
+ 					ifTrue: [allowedArea := self reduceByFlaps: allowedArea]]].
- 	].
- 	(Smalltalk isMorphic and: [self respondsTo: #reduceByFlaps:]) ifTrue:
- 		[allowedArea := self reduceByFlaps: allowedArea].
  	^allowedArea!