Fixed cursors moving around with removal and inserts with cursors. Also fixed drawing line highlights with multicursors.

data/core/doc/init.lua

@@ -322,6 +322,7 @@ end
 function Doc:raw_insert(line, col, text, undo_stack, time)
   -- split text into lines and merge with line at insertion point
   local lines = split_lines(text)
+  local len = #lines[#lines]
   local before = self.lines[line]:sub(1, col - 1)
   local after = self.lines[line]:sub(col)
   for i = 1, #lines - 1 do
@@ -338,6 +339,15 @@ function Doc:raw_insert(line, col, text, undo_stack, time)
   push_undo(undo_stack, time, "selection", unpack(self.selections))
   push_undo(undo_stack, time, "remove", line, col, line2, col2)
 
+  -- keep cursors where they should be
+  for idx, cline1, ccol1, cline2, ccol2 in self:get_selections(true) do
+    if cline1 >= line then 
+      local line_addition = line > cline1 or ccol1 > col and #lines - 1 or 0
+      local column_addition = line == cline1 and ccol1 > col and len or 0
+      self:set_selections(idx, cline1 + line_addition, ccol1 + column_addition, cline2 + line_addition, ccol2 + column_addition)
+    end
+  end
+
   -- update highlighter and assure selection is in bounds
   self.highlighter:invalidate(line)
   self:sanitize_selection()
@@ -356,6 +366,15 @@ function Doc:raw_remove(line1, col1, line2, col2, undo_stack, time)
 
   -- splice line into line array
   common.splice(self.lines, line1, line2 - line1 + 1, { before .. after })
+  
+  -- move all cursors back if they share a line with the removed text
+  for idx, cline1, ccol1, cline2, ccol2 in self:get_selections(true) do
+    if cline1 >= line2 then
+      local line_removal = line2 - line1
+      local column_removal = line2 == cline2 and col2 < ccol1 and (line2 == line1 and col2 - col1 or col2) or 0
+      self:set_selections(idx, cline1 - line_removal, ccol1 - column_removal, cline2 - line_removal, ccol2 - column_removal)
+    end
+  end
 
   -- update highlighter and assure selection is in bounds
   self.highlighter:invalidate(line1)