Step back slowly from the simulator, then actually think about the circuit, not the simulation.
Remember what a perfect voltage source does. It always presents its voltage accross its terminals, regardless of what impedance you connect to it, or equivalently, what kind of current you draw from it.
The capacitors and resistor are just loads on the voltage source. They will cause it to produce some current to maintain the voltage, but by definition, it will maintain the voltage. Another way of looking at this is that a ideal voltage source has 0 impedance. Therefore paralleling it with any other non-zero impedance isn't going to change the voltage.
What you are probably confused by is that in the real world there are no such things as ideal voltage sources. They all have some equivalent series impedance, and can only supply up to some maximum current. A battery, for example, may have 1.5 V accross it open-circuit, but go down to 1.2 V when you draw one amp. Ideal voltage sources in simulators don't do that. You can model that to some extent by putting a resistance in series with a ideal voltage source. However, perfect ideal voltage sources only exist in the land of simulators and unicorns.