How to set language icon manually?

I can set this icon when I create a new project but if I forgot to do it where can I set this icon in the control panel?

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The Icon will automatically be set when events come in.
In this project, for example I have both JavaScript and C# events:

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Here I only have C# events:

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And here, like in your example, I have no events:

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The thing is, mine doesn’t change icons like it suppose to. Is there a way to change icon(s) manually?