On "JarRecipe - Manifest" window, you can see the
following messages:

- Manifest Text:
- Attributes:

Mnemonic key is set on the each first char.

=== ManifestTab.java
manifestTextLabel.setText(java.util.ResourceBundle.getBundle("org/netbeans/modules/jarpackager/Bundle").getString("CTL_ManifestText"));
manifestTextLabel.setDisplayedMnemonic(manifestTextLabel.getText().charAt(0));

generationLabel.setText(java.util.ResourceBundle.getBundle("org/netbeans/modules/jarpackager/Bundle").getString("CTL_GenerationBorder"));
generationLabel.setDisplayedMnemonic(generationLabel.getText().charAt(0));

But such implementation makes mnemonic keys 
go wrong after translation.
Because the first letter of the translated
message is double-byte char. 

Please add the new messages into the Bundle,
and implement them like follows:

====
manifestTextLabel.setText(org.openide.util.NbBundle.getBundle("org/netbeans/modules/jarpackager/Bundle").getString("CTL_ManifestText"));
manifestTextLabel.setDisplayedMnemonic(org.openide.util.NbBundle.getBundle("org/netbeans/modules/jarpackager/Bundle").getString("CTL_ManifestText_MNE").charAt(0));