Same, can confirm for 1.14.2 pre-3
Apologies, but best if we actually name the bug correctly, you have 'if' instead of 'of'
Oddly, since I don't know what changed inbetween 3.2.1, and 3.2.2, if you update to 3.2.2+ it should be working much better.
Note, this is only for MultiMC that this file works, i don't know about the default launcher currently, will update if I find out.
https://raw.githubusercontent.com/Dinolek/LWJGL-MultiMC/master/3.2.2.json
I'd try doing that, but I don't quite know how to do that for multimc or minecraft
I also am not sure about changing the lwjgl.json file with the vanilla launcher, and with multimc, it crashes after I tried changing the lwjgl.json file (since changing the lwjgl version is glitchy), so I'm at a loss here..
Same on Ubuntu 18.04 XFCE, both MultiMC and vanilla launcher. all pre-releases are doing it to me..
Try updating your lwjgl using above guides and see if that fixes it for you