The IKEA VIDGA curtain rail system uses some flimsy plastic tabs to connect the rails together. These tend to become loose and/or break over time. IKEA doesn't sell these separately and the only way that you can address this is by purchasing a whole new VIDGA rail that includes these tabs. A waste of money and materials. I found an easy fix using some nuts and bolts and a few washers, and ivtry to explain how this works in this short video. I hope some of you find it useful, and let me know in the comments if you have any questions that I may be able to answer. Thanks!