Fixes for scrolling

src/com/maddyhome/idea/vim/action/motion/scroll/MotionScrollHalfPageDownAction.kt

@@ -21,11 +21,16 @@ import com.intellij.openapi.actionSystem.DataContext
 import com.intellij.openapi.editor.Editor
 import com.maddyhome.idea.vim.VimPlugin
 import com.maddyhome.idea.vim.command.Command
+import com.maddyhome.idea.vim.command.CommandFlags
 import com.maddyhome.idea.vim.handler.VimActionHandler
+import com.maddyhome.idea.vim.helper.enumSetOf
+import java.util.*
 
 class MotionScrollHalfPageDownAction : VimActionHandler.SingleExecution() {
   override val type: Command.Type = Command.Type.OTHER_READONLY
 
+  override val flags: EnumSet<CommandFlags> = enumSetOf(CommandFlags.FLAG_IGNORE_SCROLL_JUMP)
+
   override fun execute(editor: Editor, context: DataContext, cmd: Command): Boolean {
     return VimPlugin.getMotion().scrollScreen(editor, cmd.rawCount, true)
   }

src/com/maddyhome/idea/vim/action/motion/scroll/MotionScrollLineDownAction.kt

@@ -21,11 +21,16 @@ import com.intellij.openapi.actionSystem.DataContext
 import com.intellij.openapi.editor.Editor
 import com.maddyhome.idea.vim.VimPlugin
 import com.maddyhome.idea.vim.command.Command
+import com.maddyhome.idea.vim.command.CommandFlags
 import com.maddyhome.idea.vim.handler.VimActionHandler
+import com.maddyhome.idea.vim.helper.enumSetOf
+import java.util.*
 
 class MotionScrollLineDownAction : VimActionHandler.SingleExecution() {
   override val type: Command.Type = Command.Type.OTHER_READONLY
 
+  override val flags: EnumSet<CommandFlags> = enumSetOf(CommandFlags.FLAG_IGNORE_SCROLL_JUMP)
+
   override fun execute(editor: Editor, context: DataContext, cmd: Command): Boolean {
     return VimPlugin.getMotion().scrollLine(editor, cmd.count)
   }

src/com/maddyhome/idea/vim/action/motion/scroll/MotionScrollLineUpAction.kt

@@ -21,11 +21,16 @@ import com.intellij.openapi.actionSystem.DataContext
 import com.intellij.openapi.editor.Editor
 import com.maddyhome.idea.vim.VimPlugin
 import com.maddyhome.idea.vim.command.Command
+import com.maddyhome.idea.vim.command.CommandFlags
 import com.maddyhome.idea.vim.handler.VimActionHandler
+import com.maddyhome.idea.vim.helper.enumSetOf
+import java.util.*
 
 class MotionScrollLineUpAction : VimActionHandler.SingleExecution() {
   override val type: Command.Type = Command.Type.OTHER_READONLY
 
+  override val flags: EnumSet<CommandFlags> = enumSetOf(CommandFlags.FLAG_IGNORE_SCROLL_JUMP)
+
   override fun execute(editor: Editor, context: DataContext, cmd: Command): Boolean {
     return VimPlugin.getMotion().scrollLine(editor, -cmd.count)
   }

src/com/maddyhome/idea/vim/command/CommandFlags.kt

@@ -53,6 +53,15 @@ enum class CommandFlags {
    * This keystroke should be saved as part of the current insert
    */
   FLAG_SAVE_STROKE,
+
+  /**
+   * Don't include scrolljump when adjusting the scroll area to ensure the current cursor position is visible.
+   * Should be used for commands that adjust the scroll area (such as <C-D> or <C-E>).
+   * Technically, the current implementation doesn't need these flags, as these commands adjust the scroll area
+   * according to their own rules and then move the cursor to fit (e.g. move cursor down a line with <C-E>). Moving the
+   * cursor always tries to adjust the scroll area to ensure it's visible, which in this case is always a no-op.
+   * This is an implementation detail, so keep the flags for both documentation and in case of refactoring.
+   */
   FLAG_IGNORE_SCROLL_JUMP,
   FLAG_IGNORE_SIDE_SCROLL_JUMP,
 

src/com/maddyhome/idea/vim/group/MotionGroup.java

@@ -603,7 +603,7 @@ public boolean scrollColumnToLastScreenColumn(@NotNull Editor editor) {
 
   public static void scrollCaretIntoView(@NotNull Editor editor) {
     final EnumSet<CommandFlags> flags = CommandState.getInstance(editor).getExecutingCommandFlags();
-    final boolean scrollJump = flags.contains(CommandFlags.FLAG_IGNORE_SCROLL_JUMP);
+    final boolean scrollJump = !flags.contains(CommandFlags.FLAG_IGNORE_SCROLL_JUMP);
     scrollPositionIntoView(editor, editor.getCaretModel().getVisualPosition(), scrollJump);
   }