What is wrong?

What triggers on mouse-down:

• Sidebar: thread item

• Sidebar: new chat button

• Sidebar: user avatar (that opens the dropdown with settings, feedback and sign out buttons)

• Sidebar: new profile form → Copy Settings From dropdown

• Chat input: reasoning effort selector

• Corner menu buttons: settings button

• User/Assistant Message: Branch Off and Retry Message buttons

• User Message: chat input actions → dropdown button

• Settings → Customization: active profile field → dropdown menu

• Settings → Customization: main text font field → dropdown menu

• Settings → Customization: code font field → dropdown menu

• Settings → History & Sync: chat history section → dropdown button

• Settings → History & Sync: chat history section → thread history table → table row + checkbox in it

• Settings → History & Sync: shared threads table → table row (not the button on it)

• Settings → Models: dropdown button

• Settings → Models: filter dropdown button

• Settings → Attachments: attachments table → file type filter dropdown button

• Settings → Attachments: attachments table → table row + checkbox in it

Why is this wrong?

Click-to-select, click-to-open, click-to-navigate and similar interactions are meant to require a full click cycle: mouse-down and mouse-up. And while none of these are critical, having them immediately trigger on mouse-down makes it impossible for the user to abort the interaction (mouse-down → move mouse away → mouse-up elsewhere). Mouse-down should only trigger something when the expected next action is holding the button (which, I think, none of these match) or when mouse dragging starts (which none of these currently implement).