My assumption is that the original poster was referring to the down state, not the active state:
once tapped they turn to blue (b) before loading the page linked to.
To clarify, the active state is the state of a button that is "selected". You would typically use this, say, to indicate which of a set of grouped buttons is currently selected.
There's a difference between "active" and "down". "down" just means the
button was pressed. "active" means you're giving the user an indication
of "on", "selected", etc.
To make a physical analogy: "down" means "pressed", or "momentarily
pressed". "active" means "lit up". Or, "active" means "pressed and
latched down". Think of a button that lights-up when it's corresponding function is active, or one where you push it once, and it stays down, and then you push it again, and it pops back up.
It can be a bit confusing.
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Themeroller allows you to set the active state style, but it is a global
style across all swatches of a theme. That doesn't really make sense
to me
Doesn't make sense to me, either. It's the JQM designers making design decisions for us, again. :( They've decided for us that it's best to have a single color to indicate "selected" across all swatches.
Why not have a separate active state color for each swatch, and if they want to encourage us to use a single color across all swatches, then default them all to the same color? But then let us change them for each swatch if we want.