Texpad allows you to open files in your projects in multiple tabs. These tabs may have different editor and PDF location, allowing you to work on different parts of the project simultaneously and easily switch between them. You can create as many tabs as you want.

osx-tabs

Creating a new tab (Cmd-Shift-T) duplicates the state of the current tab and makes the new tab current. Cmd-Shift-[ and Cmd-Shift-] allow you to quickly move to the next and previous tabs.