Paying for Sunburst

**Is your feature request related to a problem? Please describe.**
When tapping lands that allow choosing a color to pay for a creature spell with sunburst, Forge arbitrarily picks colors to use as colorless mana, often leading to less-than-optimum results.

**Describe the solution you'd like**
I'd like Forge to always prompt for which color mana to use when tapping a source that offers such a choice.

**Describe alternatives you've considered**
In cases where only one option has not already been used, Forge could automatically pick the previously unpicked color to maximize the number of +1/+1 counters. However, there may be times when having a smaller creature is preferable, e.g. if Ensnaring Bridge is on the battlefield.

**Additional context**
Currently, I work around this issue by tapping for mana before clicking the spell to cast. However, this isn't always an option, e.g. when a sunburst card is selected by cascade. Another workaround is using Dev Mode to add counters, but this too doesn't always work, because there may be global toughness-reducing effects that could cause the creature to die if it lacks sufficient +1/+1 counters.