Looking at the guild chat window the only thing I can see causing the problem is this block of code. I'm not seeing anything that saves anything in this part of the code and if I recall rightly I based it on the minimap and combat log windows so I will see if I can spot something I can add to do that specifically.
Until then I assume that if you adjust the fontsize in the block of code near the top of the lua file it will keep to that size.
Code:
nUI_InfoPanels[nUI_INFOPANEL_GUILDCHAT] =
{
enabled = true,
desc = nUI_L[nUI_INFOPANEL_GUILDCHAT], -- player friendly name/description of the panel
label = nUI_L[nUI_INFOPANEL_GUILDCHAT.."Label"], -- label to use on the panel selection button face
rotation = nUI_INFOMODE_GUILDCHAT, -- index or position this panel appears on/in when clicking the selector button
full_size = true; -- this plugin requires the entire info panel port without the button bag
options =
{
enabled = true,
fontsize = 11,
btn_size = 45,
btn_gap = -8,
},
};