Error: Connection is closed due to `settings.json`, `launch.json`, and `tasks.json` ?

Description

I am not sure but every time I close the electron application (started from source) I see the following error in the console:

root ERROR Uncaught Exception:  Error: Connection is closed.
root ERROR Error: Connection is closed.
    at throwIfClosedOrDisposed (/Users/akos.kitta/git/theia/node_modules/vscode-jsonrpc/lib/main.js:673:19)
    at Object.sendRequest (/Users/akos.kitta/git/theia/node_modules/vscode-jsonrpc/lib/main.js:782:13)
    at /Users/akos.kitta/git/theia/packages/core/lib/common/messaging/proxy-factory.js:310:72
    at new Promise (<anonymous>)
    at /Users/akos.kitta/git/theia/packages/core/lib/common/messaging/proxy-factory.js:303:24
    at process._tickCallback (internal/process/next_tick.js:68:7)
root ERROR Uncaught Exception:  Error: The channel has been disposed.
root ERROR Error: The channel has been disposed.
    at WebSocketChannel.checkNotDisposed (/Users/akos.kitta/git/theia/packages/core/lib/common/messaging/web-socket-channel.js:52:19)
    at WebSocketChannel.close (/Users/akos.kitta/git/theia/packages/core/lib/common/messaging/web-socket-channel.js:92:14)
    at WebSocket.<anonymous> (/Users/akos.kitta/git/theia/packages/core/lib/node/messaging/messaging-contribution.js:198:29)
    at WebSocket.emit (events.js:187:15)
    at WebSocket.emitClose (/Users/akos.kitta/git/theia/packages/core/node_modules/ws/lib/websocket.js:193:10)
    at Socket.socketOnClose (/Users/akos.kitta/git/theia/packages/core/node_modules/ws/lib/websocket.js:861:15)
    at Socket.emit (events.js:182:13)
    at TCP._handle.close (net.js:606:12)
root ERROR Uncaught Exception:  Error: Connection is closed.
root ERROR Error: Connection is closed.
    at throwIfClosedOrDisposed (/Users/akos.kitta/git/theia/node_modules/vscode-jsonrpc/lib/main.js:673:19)
    at Object.sendRequest (/Users/akos.kitta/git/theia/node_modules/vscode-jsonrpc/lib/main.js:782:13)
    at /Users/akos.kitta/git/theia/packages/core/lib/common/messaging/proxy-factory.js:310:72
    at new Promise (<anonymous>)
    at /Users/akos.kitta/git/theia/packages/core/lib/common/messaging/proxy-factory.js:303:24

I added some console logging:

diff --git a/packages/core/src/common/messaging/proxy-factory.ts b/packages/core/src/common/messaging/proxy-factory.ts
index 27676d312..043de3469 100644
--- a/packages/core/src/common/messaging/proxy-factory.ts
+++ b/packages/core/src/common/messaging/proxy-factory.ts
@@ -239,7 +239,10 @@ export class JsonRpcProxyFactory<T extends object> implements ProxyHandler<T> {
                         } else {
                             const resultPromise = connection.sendRequest(method, ...args) as Promise<any>;
                             resultPromise
-                                .catch((err: any) => reject(this.deserializeError(capturedError, err)))
+                                .catch((err: any) => {
+                                    console.log(`error when requesting '${method}' with args: {${JSON.stringify(args)}}`, err);
+                                    reject(this.deserializeError(capturedError, err));
+                                })
                                 .then((result: any) => resolve(result));
                         }
                     } catch (err) {

Finally, I could see the real issue:

root INFO error when requesting 'resolveContent' with args: {["file:///Users/akos.kitta/git/theia/.theia/tasks.json",null]} Error
    at handleResponse (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:80023:36)
    at processMessageQueue (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79847:9)
    at Immediate.<anonymous> (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79830:7)
    at runCallback (timers.js:694:18)
    at tryOnImmediate (timers.js:665:5)
    at processImmediate (timers.js:647:5)
root INFO [nsfw-watcher: 15573] Started watching: /Users/akos.kitta/git/theia/.vscode/settings.json
root INFO error when requesting 'resolveContent' with args: {["file:///Users/akos.kitta/git/theia/.theia/launch.json",null]} Error
    at handleResponse (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:80023:36)
    at processMessageQueue (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79847:9)
    at Immediate.<anonymous> (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79830:7)
    at runCallback (timers.js:694:18)
    at tryOnImmediate (timers.js:665:5)
    at processImmediate (timers.js:647:5)
root INFO error when requesting 'resolveContent' with args: {["file:///Users/akos.kitta/git/theia/.vscode/tasks.json",null]} Error
    at handleResponse (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:80023:36)
    at processMessageQueue (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79847:9)
    at Immediate.<anonymous> (file:///Users/akos.kitta/git/theia/examples/electron/lib/bundle.js:79830:7)
    at runCallback (timers.js:694:18)
    at tryOnImmediate (timers.js:665:5)
    at processImmediate (timers.js:647:5)

On app stop, something tries to resolve the content of the settings.json, launch.json and tasks.json files. I do not see the same errors with the browser example. I do not know if this is an electron issue only.

Reproduction Steps

Build and start theia electron from the source. Close the app with Cmd+Q (on macOS).

OS and Theia version: macOS f255f5a8c

Diagnostics: