Electron desktopCapturer window capture lag and high latency

Question

When I try to capture a window in Electron I get a very laggy (around 15fps) and high latency result, but when I capture the entire screen it works just fine.

Maybe it is because I'm running getSource() under createWindow(), but again screen capture works just fine.

I'm using basically the same code in https://www.electronjs.org/docs/latest/api/desktop-capturer

function createWindow() {

...

  function getSource() {
    desktopCapturer.getSources({ types: ["window", "screen"] }).then(async (sources) => {
      for (const source of sources) {
        if (source.name.toLowerCase().includes("screen 1")) {
          // if (source.name === "Screen 1") {
          mainWindow.webContents.send("SET_SOURCE", source.id);
          return;
        }
        console.log(source.name);
      }
    });
  }
  getSource();
}

I already tried adding frame rate limitations:

...

      video: {
        mandatory: {
          chromeMediaSource: "desktop",
          chromeMediaSourceId: sourceId,
          minFrameRate: 30, // here
          maxFrameRate: 60,
          minWidth: 1280,
          maxWidth: 1280,
          minHeight: 720,
          maxHeight: 720,
        },

...