Solution 1:

In this case, you don't even need a ternary operator:

 cmdCse.setVisible(selection.toLowerCase().equals("produkt"));

Or, cleaner:

 cmdCse.setVisible(selection.equalsIgnoreCase("produkt"));

Your version:

selection.toLowerCase().equals("produkt")? cmdCse.setVisible(true): cmdCse.setVisible(false);

is semantically incorrect: ternary operator should represent alternative assignments, it's not a full replacement for if statements. This is ok:

double wow = x > y? Math.sqrt(y): x;

because you are assigning either x or Math.sqrt(y) to wow, depending on a condition.

My 2cents: use ternary operator only when it makes your program clearer, otherwise you will end up having some undecipherable one-liners.

Solution 2:

Perhaps

cmdCse.setVisible(selection.toLowerCase().equals("produkt"));