[ui] Fix focus stealing, minor style fixes.

ui.lua

@@ -99,7 +99,7 @@ function Ui.new(args)
     self.w,self.h = root.w,root.h
 
     local firstfocus, cancelfocus = resolveautofocus(root)
-    if firstfocus == nil then
+    if not firstfocus then
         firstfocus = isinstance(root, Layout) and
                      root:first() or
                      root
@@ -115,34 +115,34 @@ end
 function Ui:keypressed(key, scancode, isrepeat)
     local focused = self.focused
 
-    if focused ~= nil and focused.grabkeyboard then
+    if focused and focused.grabkeyboard then
         focused:keypressed(key, scancode, isrepeat)
     end
 end
 function Ui:keyreleased(key, scancode)
     local focused = self.focused
 
-    if focused ~= nil and focused.grabkeyboard then
+    if focused and focused.grabkeyboard then
         focused:keyreleased(key, scancode)
     end
 end
 function Ui:textinput(text)
     local focused = self.focused
 
-    if focused ~= nil and focused.grabkeyboard then
+    if focused and focused.grabkeyboard then
         focused:textinput(text)
     end
 end
 function Ui:textedited(text, start, length)
     local focused = self.focused
 
-    if focused ~= nil and focused.grabkeyboard then
+    if focused and focused.grabkeyboard then
         focused:textedited(text, start, length)
     end
 end
 
 local function actionpropagate(widget, action)
-    while widget ~= nil do
+    while widget do
         if widget:onActionInput(action) then
             return true  -- action consumed
         end
@@ -166,7 +166,10 @@ end
 
 local function eventpropagate(ui, snap)
     -- 1. Pointer events
-    if snap.pointer and not ui.grabpointer then
+    local dropPointer = ui.focused and ui.focused.grabpointer
+    local dropAction = ui.focused and ui.focused.grabkeyboard
+
+    if snap.pointer and not dropPointer then
         local root = ui[1]
         local x,y,w,h = root.x,root.y,root.w,root.h
 
@@ -176,7 +179,7 @@ local function eventpropagate(ui, snap)
     end
 
     -- 2. Actions (keyboard/buttons)
-    if snap.action and not ui.grabkeyboard then
+    if snap.action and not dropAction then
         local consumed = actionpropagate(ui.focused, snap)
 
         if not consumed then