Gcode viewer: Opening settings causes layers to vanish from model

[foosel]

Problem

When opening the settings while the gcode viewer is active, the model loses the first two layers. Opening settings again and again can make the whole model disappear from memory.

The bug can be seen by the viewer seeming to switch to a new layer after every opening of the settings, even though the viewer still claims to be at the first one.

The layers are also no longer sorted.

Steps:

• Connect to virtual printer, select a file
• switch to gcode viewer, let file load
• open settings, close settings
• note that a different layer is shown

JS Console with 22d7392 applied shows this on repeated openings:

Rerendering layer 0 of 16 with 1636 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 15 with 1125 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 14 with 1395 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 14 with 1395 segments
packed_core.js?777f4219:11018 [Violation] 'load' handler took 306ms
packed_core.js?777f4219:9085 Rerendering layer 0 of 13 with 1517 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 12 with 1162 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 12 with 1162 segments
packed_core.js?777f4219:11018 [Violation] 'load' handler took 172ms
packed_core.js?777f4219:9085 Rerendering layer 0 of 11 with 1160 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 10 with 1509 segments
packed_core.js?777f4219:9085 Rerendering layer 0 of 10 with 1509 segments

Notice the decreasing layer count.

[foosel]

Fixed by the above commit, pushed to maintenance, soon devel, to be part of 1.3.12.