Summary

@joernhees realized disappearing GitGutter icons after scrolling the view up and down quickly.

We discussed his problem in jisaacks/GitGutter#452 (comment) and tried to find the reason. After several steps we finally ended up with the remaining issue even in a vanilla install after adding a bunch of "dummy" regions to a text file of 50 or 600 lines (count doesn't matter). Therefore it looks like an OS related issue of Sublime Text on MacOS.

Expected behavior

Gutter icons must not disappear by scrolling.

Actual behavior

Some of the gutter icons disappear when scrolling in a view.

Steps to reproduce

1. Create a plugin with the content from below.
2. Open ST without any packages installed.
3. Open a text file with a bunch of lines.
4. Run view.run_command("debug_add_regions") to add a gutter icon to each line.
5. Scroll quickly up and down in the text file.

import sublime
import sublime_plugin


class DebugAddRegionsCommand(sublime_plugin.TextCommand):

    def run(self, edit):
        sublime.set_timeout_async(self.run_async, 0)


    def run_async(self):
        region = sublime.Region(0, self.view.size())
        regions = [sublime.Region(r.a, r.a + 1) for r in self.view.lines(region)]

        self.view.add_regions(
            'debug_region',
            regions=regions,
            scope='markup.changed',
            icon='Packages/Theme - Default/common/dot.png',
            flags=sublime.DRAW_NO_FILL | sublime.DRAW_NO_OUTLINE)

Environment

• Operating system and version:
  • Mac OS ...
• Monitor:
  • Resolution ...
  • dpi_scale used in ST ...
• Sublime Text:
  • Build 3143
  • 64 bit