Set z-index of synteny highlights, sort Zmenu areas in reverse of rendering order

[twalsh-ebi]

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Description

This draft PR would assign z-index values to synteny highlights, and would sort non-draggable image-map areas in reverse of rendering order.

The benefit of this would be more intuitive behaviour of image-map ZMenus in views that have overlapping clickable elements, such as the synteny view.

Views affected

Synteny view

• Tongue sole synteny view: sandbox vs staging site

The following example images show the tongue sole synteny view, with red arrows linking Zmenus to the synteny regions for which they are generated.

On the staging site, clicking on a visible synteny region may bring up a Zmenu that is not for that synteny region, but rather for another synteny region obscured by it:

On the sandbox, clicking on a visible synteny region brings up the ZMenu for that region:

Possible complications

This could potentially affect any Ensembl view with an image map.

The following table lists image-map views that have been tested for possible issues.

During initial checks, an issue was identified with how this update deals with views containing draggable areas, and the pull request has since been updated to revert to the previous behaviour in the case of draggable areas.

view_name	sandbox_view	staging_view	tested
Chromosome summary	sandbox	staging	headings; chromosome bands; histogram
Gene summary	sandbox	staging	gene tracks; contig tracks; regulatory features
Gene tree	sandbox	staging	gene-tree nodes; leaf labels
Gene Variant Image	sandbox	staging	variant tracks; gene tracks; domain tracks
Image alignment	sandbox	staging	gene tracks; contig tracks; alignment bands
LD view	sandbox	staging	chromosome bands; gene tracks; variant track; LD plots
Protein summary	sandbox	staging	exon track; protein domain tracks; protein feature tracks; variant tracks; mutation tracks
Region comparison	sandbox	staging	chromosome bands; contig tracks; gene tracks; alignment bands; regulatory features
Region in detail	sandbox	staging	chromosome bands; constrained elements; gene tracks; gnomAD short variants; phenotype-associated short variants; gnomAD structural variants; regulatory features; Age of Base
Region overview	sandbox	staging	chromosome bands; tile path; gene tracks
Splice variants	sandbox	staging	transcript tracks; domain tracks
Structural variants	sandbox	staging	gene tracks; contig tracks; structural variant tracks; regulatory features
Transcript Variant Image	sandbox	staging	variant tracks; gene tracks; domain tracks
Whole genome	sandbox	staging	chromosome bands

Merge conflicts

None detected.

Related JIRA Issues (EBI developers only)

• N/A