Operating system: Windows-8.1-6.3.9600 64 Bits
Graphics card: GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 417.22
Broken: version: 2.80 (sub 48), branch: master, commit date: 2019-03-15 00:41, hash: rB388ff003e28b
Short description of error
I've noticed this behavior in both Blender 2.79 and Blender 2.8. When scrubbing the cursor over a track containing audio, the video preview disappears, but if scrubbing over a track containing video, it remains.
From a video editing perspective, this behavior would be considered undesirable. But it also makes animation (with an open video preview window for lip sync) extremely difficult as you cannot scrub logically over the audio waveforms, you instead have to scrub over a video track or scrub on the Timeline window itself to avoid the video preview vanishing.
Generally, an editor wants to preview the entire contents of their timeline regardless of where they scrub, not just the track where their cursor is hovering. If they wanted a single track they would use a solo/mute button to achieve this. Please let me know if there is a setting to keep the video preview active at all times regardless of selected track if such functionality already exists and I am unaware of it.
Thank you so much! :-)