# Aligning Conditional Controls in Manipulate

Consider the following code

Manipulate[a,
Dynamic@Grid[{
{"Check 1", Control[{{a, 0, ""}, {1, 0}}]},
If[a == 1, {"Check 1.1", Control[{{aa, 0, ""}, {1, 0}}]},
Unevaluated[Sequence[]]],
If[a == 1, {"Check 1.2", Control[{{ab, 0, ""}, {1, 0}}]},
Unevaluated[Sequence[]]]
},
Alignment -> {{Right, Left}, Automatic}],
ControlPlacement -> Left]  Is it possible to use only one If for both controls Check 1.1 and Check 1.2?

Using Flatten, for example,

Manipulate[a,
Dynamic@Grid[{
{"Check 1", Control[{{a, 0, ""}, {1, 0}}]},
If[a == 1, Flatten[{
{"Check 1.1", Control[{{aa, 0, ""}, {1, 0}}]},
{"Check 1.2", Control[{{ab, 0, ""}, {1, 0}}]}
}],
Unevaluated[Sequence[]]]
},
Alignment -> {{Right, Left}, Automatic}],
ControlPlacement -> Left]


I get which is not what I want. I tried playing around with Column or Row but no success. Any ideas?

Also, is there a better or faster way of doing something like this? I'm using Dynamic to be able to do it, but I wonder if Mathematica already has something to do this kind of things.

Use Apply[Sequence] instead of Flatten:
Manipulate[a, 