<C-U> and <C-O> don't work when using Japanese IM with "Windows-like shortcuts" turned on

src/MacVim/MMTextViewHelper.m

@@ -151,20 +151,22 @@ - (void)keyDown:(NSEvent *)event
     id mmta = [[[self vimController] vimState] objectForKey:@"p_mmta"];
     NSString *string = [event characters];
     NSString *unmod  = [event charactersIgnoringModifiers];
+    BOOL modCommand = (flags & NSEventModifierFlagCommand) ? YES : NO;
+    BOOL modControl = (flags & NSEventModifierFlagControl) ? YES : NO;
+    BOOL modOption = (flags & NSEventModifierFlagOption) ? YES : NO;
+    BOOL modShift = (flags & NSEventModifierFlagShift) ? YES : NO;
 
     // Alt key presses should not be interpreted if the 'macmeta' option is
     // set.  We still have to call interpretKeyEvents: for keys
     // like Enter, Esc, etc. to work as usual so only skip interpretation for
     // ASCII chars in the range after space (0x20) and before backspace (0x7f).
     // Note that this implies that 'mmta' (if enabled) breaks input methods
     // when the Alt key is held.
-    if ((flags & NSEventModifierFlagOption)
-            && [mmta boolValue] && [unmod length] == 1
+    if (modOption && [mmta boolValue] && [unmod length] == 1
             && [unmod characterAtIndex:0] > 0x20) {
         ASLogDebug(@"MACMETA key, don't interpret it");
         string = unmod;
-    } else if (imState && (flags & NSEventModifierFlagControl)
-            && !(flags & (NSEventModifierFlagOption|NSEventModifierFlagCommand))
+    } else if (imState && (modControl && !modCommand && !modOption)
             && [unmod length] == 1
             && ([unmod characterAtIndex:0] == '6' ||
                 [unmod characterAtIndex:0] == '^')) {
@@ -173,23 +175,28 @@ - (void)keyDown:(NSEvent *)event
         [self doKeyDown:@"\x1e"];
         string = nil;
     } else {
-        // HACK!  interpretKeyEvents: may call insertText: or
-        // doCommandBySelector:, or it may swallow the key (most likely the
-        // current input method used it).  In the first two cases we have to
-        // manually set the below flag to NO if the key wasn't handled.
-        interpretKeyEventsSwallowedKey = YES;
-        [textView interpretKeyEvents:[NSArray arrayWithObject:event]];
-        if (interpretKeyEventsSwallowedKey)
-            string = nil;
-        else if (flags & NSEventModifierFlagCommand) {
+        // When using JapaneseIM with "Windows-like shortcuts" turned on,
+        // interpretKeyEvents: does not call doCommandBySelector: with Ctrl-O
+        // and Ctrl-U (why?), so we cannot handle them at all.
+        // As a workaround, we do not call interpretKeyEvents: when no marked
+        // text and with only control-modifier.
+        if ([self hasMarkedText] || (!modControl || modCommand || modOption)) {
+            // HACK!  interpretKeyEvents: may call insertText: or
+            // doCommandBySelector:, or it may swallow the key (most likely the
+            // current input method used it).  In the first two cases we have to
+            // manually set the below flag to NO if the key wasn't handled.
+            interpretKeyEventsSwallowedKey = YES;
+            [textView interpretKeyEvents:[NSArray arrayWithObject:event]];
+            if (interpretKeyEventsSwallowedKey)
+                string = nil;
+        }
+        if (string && modCommand) {
             // HACK! When Command is held we have to more or less guess whether
             // we should use characters or charactersIgnoringModifiers.  The
             // following heuristic seems to work but it may have to change.
             // Note that the Shift and Alt flags may also need to be cleared
             // (see doKeyDown:keyCode:modifiers: in MMBackend).
-            if ((flags & NSEventModifierFlagShift
-                    && !(flags & NSEventModifierFlagOption))
-                    || flags & NSEventModifierFlagControl)
+            if ((modShift && !modOption) || modControl)
                 string = unmod;
         }
     }