F7-visual Studio-switch between aspx and "Codebehind"

It is not a working for me. What I had to do:

• Bring up customization dialog with "Tools\operations ..."
• Bring up the keystroke mapper with "Keyboard ..."
• Set focus in "press Shortcut Keys" text box
• Press F7 or some other keystroke you want
• The "Shortcut currently used by" box would show the command currently invoked by the keystroke.
• Set focus to "Show Commands containing" and type Toggledesigner
• This would select the View.toggledesigner command in the list box of commands
• Next press the "Assign" button to Assign the keystroke shortcut to the command.
• Click "OK" to the Keystroke Mapper dialog
• Click "Close" to the customization dialog

F7-visual Studio-switch between aspx and "Codebehind"