Squeak smalltalk: why can't I activate the do it menu

I downloaded squeak 4.2 http://squeak.org/ and watch this very basic tutorial http://www.youtube.com/watch?v=0w1Yub4eUAU

When I type 2 + 2 in wor开发者_StackOverflow社区kspace window and select right-click the line I can't get any popup menu with "do it" option.

Did I miss something ?

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Depending on your platform and configuration that menu may be activated either by a right-click or a middle-click. For Squeak on Windows I believe the default is to middle-click.

If the default feels unintuitive you can invert the right and middle mouse buttons.

To invert the mouse buttons for the current image:

• Click on the world background
• Select open... from the World menu
• Select Preference Browser
• Search for mouse in the preferences
• Toggle swapMouseButtons

To invert the mouse buttons on the Windows VM:

• Open the system menu (small Squeak icon in the top-left window corner)
• Under VM Preferrences > Mouse mapping toggle 3 button mouse

You can also activate that menu by ALT-clicking or use the quicker ALT-d shortcut for "do it".