I use Electrum wallet (version 4.3.2) on tesnet (apple desktop). The testnet balance is 0.02 tBTC. Under the 'Channels' tab, the option 'Open Channel' is there but it is not clickable.
Is LN testnet supported by Electrum ?
I am not sure what is different in latest version of Electrum, however I could reproduce the issue in version 4.3.2 and it works fine in version 4.3.0
Maybe you can create an issue in Electrum Github repo: https://github.com/spesmilo/electrum