Bug 69424 TVT3.0: Multiple Mnemonics in Tasks -> Filters
From the main Workbench view, click the Task menu (drop down arrow) and select Filters. There are duplicated mnemonics for (D). See the attached screenshot.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MnemonicAssigner.java
return result;
    }
    
    /**
     * Suggests a unique mnemonic for the given input string and reserves it, preventing
     * future conflicts
     * 
     * @param inputString
     * @return
     * @since 3.1
     */
    public String assign(String inputString) {
        String result = suggest(inputString);
        reserve(result);
        return result;
    }
    
    /**
     * Reserves the mnemonic that is currently being used by the given input string
     * 
     * @param inputString
     * @since 3.1
     */
    public void reserve(String inputString) {
       reserve(getMnemonic(inputString)); 
    }
    
    /**
     * Suggests a unique mnemonic for the given input string that does not conflict with 
     * any existing mnemonics.