The user interface browser is a powerful tool to navigate among objects while designing the user interface, but unfortunately it has an annoying bug: apparently it regenerates every time you switch back and forth to another window of the workspace.
Let me explain: even if you right-click on the browser and collapse all elements so that when you click on 'Panels' only the list of panels appears, if you switch to another window (it doesn't matter whether another UIR or C or H file) and return to the previous window, the browser is now expanded at the maximum detail.
This is annoying in case of UIR files with several panels and objects when you are editing a particular element in a panel and collapse the browser tree to locate that element easily: if you happen to switch the window (e.g. because you go and look at that object code) when you return to the UIR editor the browser tree is expanded at full detail 
and you need to relocate your object among a crowded list 
Since jumping from an UI element to the corresponding item in the browser tree is still a missing feature, at least preserve the state of the bowser tree to avoid wasting time each time to locate the desired item in it!