Configuring invalid keysym does not show error

[matthijskooijman]

Describe the bug

Using an invalid keysym is silently ignored and sends a NoSymbol (keysym 0) instead of showing an error message. For example, using the following gesture:

    <gesture type="PINCH" fingers="3" direction="OUT">
      <action type="SEND_KEYS">
        <keys>SomeRandomValue</keys>
      </action>
    </gesture>

Expected behaviour

I would expect an error to be shown on stdout/stderr, preferably on toucheg startup, or otherwise when the action is triggered.

Actual behaviour

Touchegg sends a NoSymbol (keysym 0) instead of showing an error message, according to xev:

KeyPress event, serial 40, synthetic NO, window 0x5800001,
    root 0x124, subw 0x0, time 657301371, (156,80), root:(157,145),
    state 0x0, keycode 204 (keysym 0x0, NoSymbol), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 40, synthetic NO, window 0x5800001,
    root 0x124, subw 0x0, time 657301372, (156,80), root:(157,145),
    state 0x0, keycode 204 (keysym 0x0, NoSymbol), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

Your environment

• Version of Touchégg: Touchégg v2.0.3.
• Operating System: Ubuntu
• Desktop Environment: Gnome

[JoseExposito]

Thanks a lot for your bug report @matthijskooijman, I'll look into this ASAP