So when I make gifs with the timeline I noticed I can't replace a frame with a new layer - for exaple I created a gif where the logo was too big and wanted to copy paste a layer form another psd document (same size) BUT it doesnt happen... It simply doesn't read it and not sure what im doing wrong - I tried deleting the animation but still doesnt show up and I need to start over if i want to change only one layer/frame.
Another thing is if I want to make similar gifs and copy the layers and paste in another .psd they appear blank even thouig the small preview shows there is content.
Assuming you are using a frame animation timeline, you can make any layer appear in any frame. In the timeline, just select the frame you want to change then turn on/off the eye icon(s) in the layers panel to make the layer(s) you want visible at that frame.
Are you sure you highlighted the frame you want to change in the frame animation time line and then set the layers palette layer visible to make its composite. You should see the frame in photoshop image window has been changed for how the visible layers composite. Make sure you set the layer opacity and blending also. I do not have an issue on windows in any version of Photoshop I have installed.
You should remove the links in your post the guideline state advertising is not proper.