Hi folks: I had an Pharo 10318 and then updat to 10328 in Linux and swapMouseButtons seems to be wrong. For the "right button" I have to press the mouse wheel button. I tried this things: Preferences setPreference: #swapMouseButtons toValue: true. Preferences setPreference: #swapMouseButtons toValue: false. Preferences enable: #swapMouseButtons. Preferences disable: #swapMouseButtons. InputSensor swapMouseButtons: false. InputSensor swapMouseButtons: true. No one do nothing. I saw http://code.google.com/p/pharo/issues/detail?id=838 and seems to be changed in 10319 However, this is not working well in Linux. What I had to do to make it work is this: Rewrite Preferences>>swapMouseButtons to this: swapMouseButtons ^ self valueOfFlag: #swapMouseButtons ifAbsent: [self break. OSPlatform current platformFamily = #Windows ifTrue: [false]. OSPlatform current platformFamily = #Unix ifTrue: [false] ] And then do: InputEventSensor swapMouseButtons: false In addition 10324 dev seems to work ok for me out of the box. Can be a problem of updating from an older version ? What can be the problem? Thanks Mariano