HexCalc D : hex dec calculator

This is a HexaDecimal calculator application.
Both Decimal and Hex values are always displayed.
Delimiter marks ,each 3 digits(Decimal) and 4 digits(Hex), are helpfull.
Larger buttons are easy to tap.
Decimal numbers are up to 18 digits and down to 10 decimal places.
Hex numbers are up to 16 digits.

[AC] is All Clear, and [BS] is BackSpace(Delete a last inputed number).
Operation is performed according to input sequences.
i.e. 2 + 3 x 4 = becomes 20.
(when "2 + 3 x ", result area becomes 5.)

Ver 1.5: Add simple history line.
Ver 1.4: Add Touch Vibrate functon.
Ver 1.3: Add ASCII code table for reference.