Bug 513217

Created attachment 187522 [details]
Glaxnimate window with vertical timeline scrollbar, but no horizontal scrollbar

SUMMARY
When additional frames are added to the timeline, they go outside the timeline panel, and there's no horizontal scrollbar to reach them. If I use the navigation keys (forward one frame, last frame), the timeline doesn't move so the selected frame is visible. Frame 1 is always visible. I've worked in other animation and video software, and horizontal scrollbar on the timeline panel is a pretty basic feature.

STEPS TO REPRODUCE
1. Create a new document, or open an existing document.
2. Simply resize the entire program window to a smaller size. (If it was fullscreen, exit fullscreen.)

Another way to reproduce (how I found it):
1. Create a new document, or open an existing document.
2. Menu: Document > Timing...
3. Increase duration. Apply.

OBSERVED RESULT
The new frames extend beyond the timeline panel, and there's no horizontal scrollbar to move beyond the initial frames. 

EXPECTED RESULT
A horizontal scrollbar that enables user to reach newly created frames, and move back and forth between frames on a longer sequence.

SOFTWARE/OS VERSIONS
Windows: 10 Pro

ADDITIONAL INFORMATION
Thankfully I have 2 screens, so I was able to detach the timeline panel and drag it wider across my secondary screen to see the added frames.

When the document is closed and opened again, the entire sequence is visible in the timeline - the frames just shrink to fit. Not sure that's the best solution for longer animations, at some point the frames will become to tiny to target precisely.

Related issue: if the timeline is undocked and I stretch it wider than the frames, the frames will stretch fill up any extra space. After dragging the timeline to a more narrow width, frames stay the same size, they don't shrink back. That leaves us again with frames cut off outside the visible timeline, and no scrollbar to get them into view.