i'm not sure how you imagine this dropdown button. could you make a mockup?
The dropdown is just the standard pedestrian control:
The useful part is how the WC_COMBOBOXW/CBS_DROPDOWNLIST control actually works.
no, the problem is
not implementation (well, in most cases, and not in this case). the problem is
design of UI/UX.
i
can make dropdown, which allows setting multiple filters. but dropdown doesn't allow to quickly show, which filters are currently set.
again, i'm open to discussion about any UI/UX elements, but they should be
acceptable for
most users.
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my development of your idea: dropdown, clicking adds/removes filter (or another variant: clicking switches current filter, ctrl+clicking adds/removes filter), 1st item resets all filters (it can be named either "reset all" or "no filters"), dropdown list shows all checked filters, and row of compact highlighted/dimmed icons without checkboxes quickly show, which filters are active.
your (and hiccup, phred) opinion?
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btw, i've changed coloring of filter icons in last plugin version, for plugin to obey current color scheme lightness - either lightness of mb skin colors (if plugin uses skin colors) or lightness of windows colors (e.g. light/dark mode).