Eclipse – Run/Debug shortcut key doesn’t work

You probably forgot to set the form's KeyPreview property to True. Overriding the ProcessCmdKey() method is the generic solution:

protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
  if (keyData == (Keys.Control | Keys.F)) {
    MessageBox.Show("What the Ctrl+F?");
    return true;
  }
  return base.ProcessCmdKey(ref msg, keyData);
}

For CTRL+F11 to work the way you want, you must set (from "Windows/Preferences") the
"Run/debug > Launching : Launch Operation" setting to:

Always launch the previously launched application

As Thorbjørn Ravn Andersen mentions in the comment, launching the last app used to be (3.2 or before) the default behavior.
Since 3.3M6 (March 2007), As illustrated by this thread:

By default, running and debugging applications has been simplified to run or debug the selected file or active editor.
When the selected resource (or active editor) is not executable, users can opt to launch the associated project or re-launch the previous launch.

These settings are managed on the Run/Debug > Launching preference page.
Users can also revert to the 3.2 behavior of always launching the previous application.

Torsten confirms in the comments:

Pressing F11 only launches the last application in debug mode.