Some dropdowns can be opened simultaneously

[adibarra]

SemiAnalysisAI/InferenceX#565

[lalithsagar10]

Root cause:
dropdowns were using mixed primitives (Select + MultiSelect) with separate open/close logic, and outside-click handling happened too late in the event chain. That caused the next dropdown click to only close the previous one (requiring a second click to open).

What we changed:
• Added a shared controlled open state (openDropdown) in each controls surface so only one menu is open at a time.
• Updated MultiSelect to support controlled open/onOpenChange.
• Switched outside-close handling to capture-phase pointerdown, enabling smooth one-click handoff between menus.
• Improved single-select mode (maxSelections=1) so selecting a new option replaces immediately in one click.
• Standardized key selectors onto MultiSelect and aligned rendering (including sectioned options + plain selected text mode).
• Fixed overlay/layering conflicts (z-index + non-portalled content where needed).

Result:
users can move from one filter dropdown to another with a single click consistently across model/sequence/precision/GPU/Y-axis and related controls.