In install() if no msg is set lyr3 is not shown, but still created and centered.
Not creating unused Layer3 could result in considerably improved speed when multiple instances of blockUI used for multiple elements without a message e.g. disable most elements except a specific mandatory set.
Removing Layer3 if no msg would require onBlock triggering to be reset.
What purpose does Layer3 serve if msg is not set.
In install() if no msg is set lyr3 is not shown, but still created and centered.
Not creating unused Layer3 could result in considerably improved speed when multiple instances of blockUI used for multiple elements without a message e.g. disable most elements except a specific mandatory set.
Removing Layer3 if no msg would require onBlock triggering to be reset.