Is my circuit faulty

Please connect the ground.

But the voltage source is fully connected.Why do I need this ground connection?

Without the ground, how is the simulator supposed to know which node is at zero volts? Connect it and try it out.

And the source must always be "fully connected", otherwise your circuit will not work.

I think it has to do with the fact that the simulator needs to actually have a voltage to calculate off of. In your circuit, I think most people would agree with you and be able to say that the node voltage should be 10V, but the issue is, the simulator needs to know 10v in reference to what? Your bottom voltage could be -100V and the circuit will still work the way you expect. Since the voltage measurements in EveryCircuit are done by a single location, this is essentially saying that you are controlling the positive/red probe on your voltmeter. The issue arises because where is the negative probe going to go (since voltage is a differential measurement)? So Everycircuit will use where ever you place that reference ground as the reference for everything else. If you are concerned about grounding the circuit and having a new current path, you could use an op-amp voltage follower to essentially make a "virtual" ground: setting that bottom node to 0V while making sure no current can flow to ground. So at the end of the day, it is a quirk of the simulator and the way it is coded. Here is a screenshot of the virtual ground in action https://i.gyazo.com/c46712ead75f04dd96a081a4b7e7378e.png

@russty it is not a quick of a simulator. The simulator will not randomly assume that the -ve terminal of a voltage source is the zero volts reference. It makes absolutely no sense whatsoever to make that assumption and go ahead with the simulation. And there is not concern regarding "grounding" and the op amp idea is unnecessary.

you can use some Megaohms, if you don't want a groundconnection.