Prefix gridContainer and controlsForm variable names with $

This helps indicate that they hold jQuery-wrapped DOM elements.
Document the makeFilterGetters 'framework'
Whitespace: Add line breaks to the hash of #negExtraCategory options
Show individual texts on multiselects if nothing is selected
Add tooltips to nontrivially intuitive controls in grid view
Only process <input> elements in makeFilterGetters if they have a name attribute
Remove right border from grid filter controls
Style grid filter controls with flexbox
Add tooltip to volume control in grid view
Shrink extension text field in grid view
Enlarge path field in grid view
Extract updateDynamicMultiselects function in grid view script
Style size and width of disk image text field in grid view