Connect to a COM port connected to a microcontroller that is serial printing once a second. Nothing is shown in the Output screen other than port connection status. Independent monitoring of the COM port with Putty shows the output from the
microcontroller.

[Edit]

Connecting to COM port does not change status Icon as I reported in #1125. Pressing F1 then Arduino: Close Serial Monitor results in:

[Starting] Opening the serial port - COM4
[Error] Failed to open the serial port - COM4
[Error]Error: Writing to COM port (GetOverlappedResult): Operation aborted
[Done] Closed the serial port

[Edit]

Works as expected on macOS Big Sur 11.0.1, MacBook Pro 2019

Version: 1.50.1 (user setup)
Commit: d2e414d9e4239a252d1ab117bd7067f125afd80a
Date: 2020-10-13T15:06:15.712Z (2 wks ago)
Electron: 9.2.1
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Windows_NT x64 10.0.19041