Making gif from video layers help

im making a gif and when i try to add text or change the brightness of all layers it only does one.
i make sure i have the first layer selected and i am at the top layer but it wont work, it worked fine for weeks and has now just stopped.
even when i shift click all the layers it just does the first layer

Make sure the text for all frames/layers has a common background. See if this helps. Also, you can use filters to reapply stuff to other layers, this can help you work faster (foward layer creates a custom set of actions that actually applies the same actions you just applied for the following layer).

HTH!