Comment 2 for bug 1719474

Sadly I noticed this yesterday with Tango skin: as soon as the scrolling waveforms are hidden the Library interaction via controller is very slow and after pressign the waveform toggle waveforms take some seconds to show up.

Hardware is a Thinkpad X220 with Intel HD Graphics 3000.
Ubuntu Studio 16.04 low-latency, everything is updated
RGB (GL) and (GLSL) tested.

Probably this was bug was introduced when I fixed
lp:1746110 "No end of track warning if Waveform Display not enabled on Tango Skin" and lp:1748170 "Log file grows rapidly" with https://github.com/mixxxdj/mixxx/pull/1512

I'll investigate if this can be solved by placing the second waveform Singleton somewhere else or with different size.