Usually in Flash, when we edit in place an instance, the 'current frame line' goes back to the first frame. We have to remember the frame you were before and move the 'current frame line' manually to see the exact frame the instance were. We spend a lot of time working that way, mainly in long timelines, where you need to scroll them.

This plugin saves you much time working with syncronized graphic symbols (when you have nested symbols). You can edit an instance and the timeline does NOT go back to the first frame. Also you can edit in place an instance selecting a key frame or a frame in the timeline, even with motion tween and there is no problem if the layer is invisible or locked.

Edit in Place Plus!
With Edit in Place, you can edit in place an instance and the 'current frame line'  goes to the right frame.
Open the Plugin by clicking Window/Other Panels/[T] Edit in Place.
Select an instance on the stage.
Press the button Edit in Place.

Also, you can edit an instance selecting a key frame or a frame in the timeline, even with motion tween and there is no problem if the layer is invisible or locked.

Select a key frame or a frame in the timeline.
Press the button Edit in Place. 
The only problem with this plugin is that once you use it, you became addicted to it... 

Learn how to assign a hotkey to this button.

Refresh in Place
When you are already editing an instance in place and drag the 'current frame line' , the instances outside don't follow it. You can fix it by clicking on the Refresh in Place button.
Editing in place an instance, move the 'current frame line'  to a frame you want.
Press the button Refresh in Place.
Important: this function only works with synchronized nested symbols.

Learn how to assign a hotkey to this button.

Exit in Place

By clicking on the Exit in Place button you exit editing an instance one level and the 'current frame line'  stays in the frame it was.
Editing in place an instance, move the 'current frame line'  to a frame you want.
Press the button Exit in Place.

Learn how to assign a hotkey to this button.