Pressing Enter key on keyboard number pad does not send message

[brianjcohen]

Steps to reproduce:

1. Launch the app on Linux (I have not tried to reproduce this on Mac or Windows).
2. Connect a physical keyboard that has a "number pad", or connect an external USB number pad device.
3. Load up a conversation and compose a message.
4. Press the Enter key on the number pad.

Expected result:

The message should be sent, the same as if you pressed Enter on the main part of the keyboard.

Actual result:

The app's text input area behaves as if "shift+Enter" had been entered on the main part of the keyboard; the cursor is moved to the beginning of a new line underneath the current line.