diff --git a/lib/capybara/session.rb b/lib/capybara/session.rb
index 3e19885e..df7a724d 100644
--- a/lib/capybara/session.rb
+++ b/lib/capybara/session.rb
@@ -363,14 +363,15 @@ module Capybara
     ##
     # @overload switch_to_window(&block)
     #   Switches to the first window for which given block returns a value other than false or nil.
+    #   If window that matches block can't be found, the window will be switched back and `WindowError` will be raised.
     #   @example
     #     window = switch_to_window { title == 'Page title' }
-    #   @return [Capybara::Window]         window that has been switched to
     #   @raise [Capybara::WindowError]     if no window matches given block
     # @overload switch_to_window(window)
     #   @param window [Capybara::Window]   window that should be switched to
     #   @raise [Capybara::Driver::Base#no_such_window_error] if unexistent (e.g. closed) window was passed
     #
+    # @return [Capybara::Window]         window that has been switched to
     # @raise [Capybara::ScopeError]        if this method is invoked inside `within`,
     #   `within_frame` or `within_window` methods
     # @raise [ArgumentError]               if both or neither arguments were provided
@@ -388,14 +389,23 @@ module Capybara
 
       if window
         driver.switch_to_window(window.handle)
+        window
       else
-        driver.window_handles.each do |handle|
-          driver.switch_to_window handle
-          if yield
-            return Window.new(self, handle)
+        original_window_handle = driver.current_window_handle
+        begin
+          driver.window_handles.each do |handle|
+            driver.switch_to_window handle
+            if yield
+              return Window.new(self, handle)
+            end
           end
+        rescue => e
+          driver.switch_to_window(original_window_handle)
+          raise e
+        else
+          driver.switch_to_window(original_window_handle)
+          raise Capybara::WindowError, "Could not find a window matching block/lambda"
         end
-        raise Capybara::WindowError, "Could not find a window matching block/lambda"
       end
     end
 
@@ -409,6 +419,7 @@ module Capybara
     # @overload within_window(window) { do_something }
     #   @param [Capybara::Window]             instance of Capybara::Window class
     #     that will be switched to
+    #   @raise [driver#no_such_window_error] if unexistent (e.g. closed) window was passed
     # @overload within_window(proc_or_lambda) { do_something }
     #   @param lambda [Proc]                  lambda. First window for which lambda
     #     returns a value other than false or nil will be switched to.
@@ -421,7 +432,6 @@ module Capybara
     #
     # @raise [Capybara::ScopeError]        if this method is invoked inside `within`,
     #   `within_frame` or `within_window` methods
-    # @raise [driver#no_such_window_error] if unexistent (e.g. closed) window was passed
     # @return                              value returned by the block
     #
     def within_window(window_or_handle)
@@ -429,20 +439,20 @@ module Capybara
         original = current_window
         begin
           switch_to_window(window_or_handle) unless original == window_or_handle
-          scopes.push(nil)
+          scopes << nil
           yield
         ensure
-          scopes.pop if scopes.last.nil? # It will be not nil if closed window has been passed
+          @scopes = [nil]
           switch_to_window(original) unless original == window_or_handle
         end
       elsif window_or_handle.is_a?(Proc)
         original = current_window
+        switch_to_window { window_or_handle.call }
+        scopes << nil
         begin
-          switch_to_window { window_or_handle.call }
-          scopes.push(nil)
           yield
         ensure
-          scopes.pop if scopes.last.nil?
+          @scopes = [nil]
           switch_to_window(original)
         end
       else
@@ -451,10 +461,10 @@ module Capybara
         warn "DEPRECATION WARNING: Passing string argument to #within_window is deprecated. "\
              "Pass window object or lambda. (called from #{file_line})"
         begin
-          scopes.push(nil)
+          scopes << nil
           driver.within_window(window_or_handle) { yield }
         ensure
-          scopes.pop
+          @scopes = [nil]
         end
       end
     end
@@ -625,7 +635,7 @@ module Capybara
     end
 
     def scopes
-      @scopes ||= [document]
+      @scopes ||= [nil]
     end
   end
 end
diff --git a/lib/capybara/spec/session/window/switch_to_window_spec.rb b/lib/capybara/spec/session/window/switch_to_window_spec.rb
index 7c8d05b8..a5855223 100644
--- a/lib/capybara/spec/session/window/switch_to_window_spec.rb
+++ b/lib/capybara/spec/session/window/switch_to_window_spec.rb
@@ -30,6 +30,17 @@ Capybara::SpecHelper.spec '#switch_to_window', requires: [:windows] do
       @session.switch_to_window(window)
       expect(['', 'about:blank']).to include(@session.title)
     end
+
+    it "should raise error when closed window is passed" do
+      original_window = @session.current_window
+      new_window = @session.open_new_window
+      @session.switch_to_window(new_window)
+      new_window.close
+      @session.switch_to_window(original_window)
+      expect do
+        @session.switch_to_window(new_window)
+      end.to raise_error(@session.driver.no_such_window_error)
+    end
   end
 
   context "with block" do
@@ -83,11 +94,21 @@ Capybara::SpecHelper.spec '#switch_to_window', requires: [:windows] do
         end
       end.to raise_error(Capybara::ScopeError, "`switch_to_window` is not supposed to be invoked from `within`'s, `within_frame`'s' or `within_window`'s' block.")
     end
-  end
 
-  it "should raise error if window matching block wasn't found" do
-    expect do
-      @session.switch_to_window { @session.title == 'A title' }
-    end.to raise_error(Capybara::WindowError, "Could not find a window matching block/lambda")
+    it "should raise error if window matching block wasn't found" do
+      original = @session.current_window
+      expect do
+        @session.switch_to_window { @session.title == 'A title' }
+      end.to raise_error(Capybara::WindowError, "Could not find a window matching block/lambda")
+      expect(@session.current_window).to eq(original)
+    end
+
+    it "should switch to original window if error is raised inside block" do
+      original = @session.switch_to_window(@session.windows[1])
+      expect do
+        @session.switch_to_window { raise 'error' }
+      end.to raise_error(StandardError, 'error')
+      expect(@session.current_window).to eq(original)
+    end
   end
 end
diff --git a/lib/capybara/spec/session/window/window_opened_by_spec.rb b/lib/capybara/spec/session/window/window_opened_by_spec.rb
index 517998b7..693d1f9d 100644
--- a/lib/capybara/spec/session/window/window_opened_by_spec.rb
+++ b/lib/capybara/spec/session/window/window_opened_by_spec.rb
@@ -18,7 +18,7 @@ Capybara::SpecHelper.spec '#window_opened_by', requires: [:windows] do
     it 'should raise error if value of :wait is less than timeout' do
       Capybara.using_wait_time 1 do
         expect do
-          @session.window_opened_by(wait: 0.3) do
+          @session.window_opened_by(wait: 0.4) do
             @session.find(:css, '#openWindowWithTimeout').click
           end
         end.to raise_error(Capybara::WindowError, zero_windows_message)
@@ -27,7 +27,7 @@ Capybara::SpecHelper.spec '#window_opened_by', requires: [:windows] do
 
     it 'should find window if value of :wait is more than timeout' do
       Capybara.using_wait_time 0.1 do
-        window = @session.window_opened_by(wait: 0.9) do
+        window = @session.window_opened_by(wait: 1) do
           @session.find(:css, '#openWindowWithTimeout').click
         end
         expect(window).to be_instance_of(Capybara::Window)
@@ -37,7 +37,7 @@ Capybara::SpecHelper.spec '#window_opened_by', requires: [:windows] do
 
   context 'without :wait option' do
     it 'should raise error if default_wait_time is less than timeout' do
-      Capybara.using_wait_time 0.2 do
+      Capybara.using_wait_time 0.4 do
         expect do
           @session.window_opened_by do
             @session.find(:css, '#openWindowWithTimeout').click
@@ -47,7 +47,7 @@ Capybara::SpecHelper.spec '#window_opened_by', requires: [:windows] do
     end
 
     it 'should find window if default_wait_time is more than timeout' do
-      Capybara.using_wait_time 0.9 do
+      Capybara.using_wait_time 1 do
         window = @session.window_opened_by do
           @session.find(:css, '#openWindowWithTimeout').click
         end
diff --git a/lib/capybara/spec/session/window/window_spec.rb b/lib/capybara/spec/session/window/window_spec.rb
index da814d02..2e854d80 100644
--- a/lib/capybara/spec/session/window/window_spec.rb
+++ b/lib/capybara/spec/session/window/window_spec.rb
@@ -54,7 +54,7 @@ Capybara::SpecHelper.spec Capybara::Window, requires: [:windows] do
     it 'should return false if window is closed' do
       @session.switch_to_window(@other_window)
       @other_window.close
-      expect(@other_window.current?).to be_false
+      expect(@other_window.current?).to eq(false)
     end
   end
 
diff --git a/lib/capybara/spec/session/window/within_window_spec.rb b/lib/capybara/spec/session/window/within_window_spec.rb
index 4df0ad5f..3b8cac9a 100644
--- a/lib/capybara/spec/session/window/within_window_spec.rb
+++ b/lib/capybara/spec/session/window/within_window_spec.rb
@@ -42,11 +42,14 @@ Capybara::SpecHelper.spec '#within_window', requires: [:windows] do
       window = (@session.windows - [@window]).first
       expect do
         @session.within_window(window) do
-          raise 'some error'
+          @session.within 'html' do
+            raise 'some error'
+          end
         end
       end.to raise_error(StandardError, 'some error')
       expect(@session.current_window).to eq(@window)
       expect(@session).to have_css('#doesNotOpenWindows')
+      expect(@session.send(:scopes)).to eq([nil])
     end
 
     it 'should raise error if closed window was passed' do
@@ -59,7 +62,9 @@ Capybara::SpecHelper.spec '#within_window', requires: [:windows] do
           raise 'should not be invoked'
         end
       end.to raise_error(@session.driver.no_such_window_error)
+      expect(@session.current_window).to eq(@window)
       expect(@session).to have_css('#doesNotOpenWindows')
+      expect(@session.send(:scopes)).to eq([nil])
     end
   end
 
@@ -86,7 +91,9 @@ Capybara::SpecHelper.spec '#within_window', requires: [:windows] do
           expect(@session).to have_css('#divInPopupOne')
         end
       end.to raise_error(Capybara::WindowError, "Could not find a window matching block/lambda")
+      expect(@session.current_window).to eq(@window)
       expect(@session).to have_css('#doesNotOpenWindows')
+      expect(@session.send(:scopes)).to eq([nil])
     end
 
     it "returns value from the block" do
@@ -103,6 +110,7 @@ Capybara::SpecHelper.spec '#within_window', requires: [:windows] do
         end
       end.to raise_error(StandardError, 'some error')
       expect(@session.current_window).to eq(@window)
+      expect(@session.send(:scopes)).to eq([nil])
     end
   end
 
@@ -110,7 +118,7 @@ Capybara::SpecHelper.spec '#within_window', requires: [:windows] do
     it "should warn" do
       expect(@session).to receive(:warn).with("DEPRECATION WARNING: Passing string argument "\
         "to #within_window is deprecated. Pass window object or lambda. "\
-        "(called from #{__FILE__}:114)").and_call_original
+        "(called from #{__FILE__}:122)").and_call_original
       @session.within_window('firstPopup') {}
     end
 
diff --git a/lib/capybara/spec/views/with_windows.erb b/lib/capybara/spec/views/with_windows.erb
index 3c5e6564..a9c410d7 100644
--- a/lib/capybara/spec/views/with_windows.erb
+++ b/lib/capybara/spec/views/with_windows.erb
@@ -12,7 +12,7 @@
       $('#openWindowWithTimeout').click(function(){
         setTimeout(function(){
           window.open('/popup_one', 'firstPopup');
-        }, 500);
+        }, 600);
         return false;
       });