fix(window-focus): preserve single-click activation

home/dot_config/aerospace/aerospace.toml

@@ -9,7 +9,7 @@ default-root-container-layout = 'tiles'
 default-root-container-orientation = 'auto'
 enable-normalization-flatten-containers = true
 enable-normalization-opposite-orientation-for-nested-containers = true
-focus-follows-mouse.enabled = true
+focus-follows-mouse.enabled = false
 key-mapping.preset = 'qwerty'
 persistent-workspaces = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']
 

home/dot_hammerspoon/clickthrough.lua

@@ -0,0 +1,45 @@
+-- Focus on mouse-down, before macOS delivers the original click to the app.
+-- Never synthesize an extra click: controls that accept first mouse must not fire twice.
+local clickthrough = {}
+local ax = require("hs.axuielement")
+local log = hs.logger.new("clickthrough", "warning")
+
+local function focusClickedWindow(event)
+    -- Leave modified clicks (context menus, background links, etc.) unchanged.
+    if next(event:getFlags()) then return false end
+    local element = ax.systemWideElement():elementAtPosition(event:location())
+    if not element then return false end
+    local role = element:attributeValue("AXRole")
+    if role == "AXMenu" or role == "AXMenuItem" or role == "AXMenuBarItem"
+        or role == "AXMenuBar" then return false end
+
+    local windowElement = element:attributeValue("AXWindow")
+    if not windowElement and role == "AXWindow" then windowElement = element end
+    local window = windowElement and windowElement:asHSWindow()
+    if not window or not window:isStandard() then return false end
+    local focused = hs.window.focusedWindow()
+    if not focused or focused:id() ~= window:id() then window:focus() end
+    return false
+end
+
+clickthrough.tap = hs.eventtap.new({hs.eventtap.event.types.leftMouseDown}, function(event)
+    local ok, err = pcall(focusClickedWindow, event)
+    if not ok then log.w(tostring(err)) end
+    return false -- Always pass through the original click, including on errors.
+end)
+
+function clickthrough.toggle()
+    clickthrough.enabled = not clickthrough.enabled
+    if clickthrough.enabled then clickthrough.tap:start() else clickthrough.tap:stop() end
+end
+
+clickthrough.enabled = true
+clickthrough.tap:start()
+-- macOS can disable event taps after sleep or a slow accessibility response.
+clickthrough.watchdog = hs.timer.doEvery(5, function()
+    if clickthrough.enabled and not clickthrough.tap:isEnabled() then
+        clickthrough.tap:start()
+    end
+end)
+
+return clickthrough

home/dot_hammerspoon/init.lua

@@ -1,5 +1,6 @@
 -- Placement rules inferred from the running windows on this Mac.
 require("hs.ipc")
+local clickthrough = require("clickthrough")
 
 local spaces = require("hs.spaces")
 local log = hs.logger.new("placement", "info")
@@ -190,6 +191,7 @@ windowPlacement = {
 }
 windowPlacement.menu:setTitle("Windows")
 windowPlacement.menu:setMenu({
+    {title = "Toggle single-click window activation", fn = clickthrough.toggle},
     {title = "Reapply placement rules", fn = restore},
     {title = "Reload configuration", fn = hs.reload},
     {title = "Open Console", fn = hs.openConsole},