If she can see out, that is rewarding in itself, so ignoring her isn't helping because she's still being "rewarded" by the view of the outside.
I would block the window. You can buy clings that turn it "frosted" or even just tape wax/baking paper over it to still let in light. Once her view is blocked, she should learn much more quickly that jumping up is both boring and doesn't get her outside. Eventually, when she has a good history of no jumping and sitting to go out, you should be able to remove the coverings without starting the habit back up, because now she has a new (more polite) habit to replace it.
I would block the window. You can buy clings that turn it "frosted" or even just tape wax/baking paper over it to still let in light. Once her view is blocked, she should learn much more quickly that jumping up is both boring and doesn't get her outside. Eventually, when she has a good history of no jumping and sitting to go out, you should be able to remove the coverings without starting the habit back up, because now she has a new (more polite) habit to replace it.