Feature request: Exclude layers from 3D right-click navigation

I love neuroglancer's right-click behavior in the 3D view, which quickly jumps to an object when I click on it. However, there's a common situation in which that feature is impaired.

When a neuron is visualized in the 3D view within a compartment mesh, then the compartment mesh "gets in the way" when I try to quickly navigate to a point on the neuron. For example, [try clicking on a neuron mesh in this view.][1] Here's a [similar example.][2] The viewer navigates to the compartment exterior, not to the neuron.

I propose an extra checkbox in the render tab to enable/disable right-click navigation.

Alternatively, it *might* suffice to simply assume that if spatial object selection is disabled for a layer, then it should also be excluded from right-click navigation in the 3D view. That would work well when the layer represents whole compartments, but I'm not completely sure if it's desirable when the layer represents internal organelles. Maybe it depends on each use-case.

[1]: https://neuroglancer-demo.appspot.com/#!%7B%22dimensions%22:%7B%22x%22:%5B8e-9%2C%22m%22%5D%2C%22y%22:%5B8e-9%2C%22m%22%5D%2C%22z%22:%5B8e-9%2C%22m%22%5D%7D%2C%22position%22:%5B25424.5%2C20996.5%2C17988.5%5D%2C%22crossSectionScale%22:16.376917105638544%2C%22crossSectionDepth%22:-37.62185354999912%2C%22projectionScale%22:36355.90703026209%2C%22layers%22:%5B%7B%22type%22:%22image%22%2C%22source%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/emdata/clahe_yz/jpeg%22%2C%22tab%22:%22source%22%2C%22name%22:%22emdata%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/segmentation%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22tab%22:%22segments%22%2C%22objectAlpha%22:0.3%2C%22colorSeed%22:40391449%2C%22segments%22:%5B%221012449420%22%2C%221039775880%22%2C%22909414983%22%2C%22946641278%22%5D%2C%22name%22:%22segmentation%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/mito-objects-grouped%22%2C%22subsources%22:%7B%22default%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22segments%22%2C%22selectedAlpha%22:0%2C%22saturation%22:0%2C%22linkedSegmentationGroup%22:%22segmentation%22%2C%22name%22:%22mito-grouped%22%7D%2C%7B%22type%22:%22annotation%22%2C%22source%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/synapses%22%2C%22tab%22:%22rendering%22%2C%22ignoreNullSegmentFilter%22:false%2C%22shader%22:%22#uicontrol%20bool%20showPsds%20checkbox%28default=true%29%5Cn#uicontrol%20vec3%20preColor%20color%28default=%5C%22red%5C%22%29%5Cn#uicontrol%20vec3%20postColor%20color%28default=%5C%22blue%5C%22%29%5Cn#uicontrol%20float%20preConfidence%20slider%28min=0%2C%20max=1%2C%20default=0%29%5Cn#uicontrol%20float%20postConfidence%20slider%28min=0%2C%20max=1%2C%20default=0%29%5Cn%5Cnvoid%20main%28%29%20%7B%5Cn%20%20setColor%28defaultColor%28%29%29%3B%5Cn%20%20%5Cn%20%20setEndpointMarkerColor%28%5Cn%20%20%20%20vec4%28preColor%2C%200.5%29%2C%5Cn%20%20%20%20vec4%28postColor%2C%200.5%29%29%3B%5Cn%20%20%5Cn%20%20if%20%28showPsds%29%20%7B%5Cn%20%20%20%20setEndpointMarkerSize%288.0%2C%204.0%29%3B%5Cn%20%20%7D%5Cn%20%20else%20%7B%5Cn%20%20%20%20setLineWidth%280.0%29%3B%5Cn%20%20%20%20setEndpointMarkerSize%288.0%2C%200.0%29%3B%5Cn%20%20%7D%5Cn%20%20%5Cn%20%20if%20%28prop_pre_synaptic_confidence%28%29%3C%20preConfidence%20%7C%7C%5Cn%20%20%20%20%20%20prop_post_synaptic_confidence%28%29%3C%20postConfidence%29%20discard%3B%5Cn%7D%5Cn%22%2C%22shaderControls%22:%7B%22showPsds%22:false%7D%2C%22linkedSegmentationLayer%22:%7B%22pre_synaptic_cell%22:%22segmentation%22%2C%22post_synaptic_cell%22:%22segmentation%22%7D%2C%22filterBySegmentation%22:%5B%22pre_synaptic_cell%22%5D%2C%22name%22:%22synapse%22%2C%22visible%22:false%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/rois%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22segments%22%2C%22selectedAlpha%22:0%2C%22saturation%22:0%2C%22objectAlpha%22:0.8%2C%22ignoreNullVisibleSet%22:false%2C%22meshSilhouetteRendering%22:3%2C%22colorSeed%22:2076506062%2C%22segments%22:%5B%2220%22%5D%2C%22name%22:%22roi%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/mito-classes%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22segments%22%2C%22segmentColors%22:%7B%224%22:%22#000000%22%7D%2C%22name%22:%22mito-classes%22%2C%22visible%22:false%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/mask_normalized_round6%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22segments%22%2C%22selectedAlpha%22:0.53%2C%22segmentColors%22:%7B%227%22:%22#000000%22%7D%2C%22name%22:%22mask%22%2C%22visible%22:false%7D%5D%2C%22showSlices%22:false%2C%22selectedLayer%22:%7B%22visible%22:true%2C%22layer%22:%22roi%22%7D%2C%22layout%22:%223d%22%7D

[2]: https://neuroglancer-demo.appspot.com/#!%7B%22dimensions%22:%7B%22x%22:%5B8e-9%2C%22m%22%5D%2C%22y%22:%5B8e-9%2C%22m%22%5D%2C%22z%22:%5B8e-9%2C%22m%22%5D%7D%2C%22position%22:%5B14877.1376953125%2C23160.591796875%2C19392.064453125%5D%2C%22crossSectionScale%22:40.28071626418804%2C%22crossSectionDepth%22:-37.62185354999912%2C%22projectionOrientation%22:%5B-0.133031964302063%2C-0.1868009716272354%2C0.00568724237382412%2C0.9733321666717529%5D%2C%22projectionScale%22:73211.80621473533%2C%22layers%22:%5B%7B%22type%22:%22image%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/emdata/clahe_yz/jpeg%22%2C%22subsources%22:%7B%22default%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22tab%22:%22source%22%2C%22name%22:%22emdata%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/segmentation%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22tab%22:%22segments%22%2C%22objectAlpha%22:0.3%2C%22segments%22:%5B%22544361987%22%2C%22942491983%22%5D%2C%22name%22:%22segmentation%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/mito-objects-grouped%22%2C%22subsources%22:%7B%22default%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22source%22%2C%22selectedAlpha%22:0%2C%22saturation%22:0%2C%22linkedSegmentationGroup%22:%22segmentation%22%2C%22name%22:%22mito-grouped%22%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://neuroglancer-janelia-flyem-hemibrain/v1.2/rois%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22source%22%2C%22selectedAlpha%22:0%2C%22saturation%22:0%2C%22objectAlpha%22:0.8%2C%22ignoreNullVisibleSet%22:false%2C%22meshSilhouetteRendering%22:3%2C%22segments%22:%5B%221%22%2C%2210%22%2C%2211%22%2C%2212%22%2C%2213%22%2C%2214%22%2C%2215%22%2C%2216%22%2C%2217%22%2C%2218%22%2C%2219%22%2C%222%22%2C%2220%22%2C%2221%22%2C%2222%22%2C%2223%22%2C%2224%22%2C%2225%22%2C%2226%22%2C%2227%22%2C%2228%22%2C%2229%22%2C%223%22%2C%2230%22%2C%2231%22%2C%2232%22%2C%2233%22%2C%2234%22%2C%2235%22%2C%2236%22%2C%2237%22%2C%2238%22%2C%2239%22%2C%224%22%2C%2240%22%2C%2241%22%2C%2242%22%2C%2243%22%2C%2244%22%2C%2245%22%2C%2246%22%2C%2247%22%2C%2248%22%2C%2249%22%2C%225%22%2C%2250%22%2C%2251%22%2C%2252%22%2C%2253%22%2C%2254%22%2C%2255%22%2C%2256%22%2C%2257%22%2C%2258%22%2C%2259%22%2C%226%22%2C%2260%22%2C%2261%22%2C%2262%22%2C%2263%22%2C%227%22%2C%228%22%2C%229%22%5D%2C%22name%22:%22roi%22%2C%22visible%22:false%7D%2C%7B%22type%22:%22segmentation%22%2C%22source%22:%7B%22url%22:%22precomputed://gs://flyem-ng-layers/hemibrain/all_brain_roi%22%2C%22subsources%22:%7B%22default%22:true%2C%22properties%22:true%2C%22mesh%22:true%7D%2C%22enableDefaultSubsources%22:false%7D%2C%22pick%22:false%2C%22tab%22:%22source%22%2C%22selectedAlpha%22:0%2C%22saturation%22:0%2C%22meshSilhouetteRendering%22:4%2C%22segments%22:%5B%221%22%5D%2C%22name%22:%22brain-mask%22%7D%5D%2C%22showSlices%22:false%2C%22selectedLayer%22:%7B%22visible%22:true%2C%22layer%22:%22mito-grouped%22%7D%2C%22layout%22:%223d%22%7D