diff --git a/aegisub/src/command/edit.cpp b/aegisub/src/command/edit.cpp
index 67f56e4b4..c3ca6cf5a 100644
--- a/aegisub/src/command/edit.cpp
+++ b/aegisub/src/command/edit.cpp
@@ -312,7 +312,10 @@ void show_color_picker(const agi::Context *c, agi::Color (AssStyle::*field), con
 	int commit_id = -1;
 	bool ok = GetColorFromUser(c->parent, color, true, [&](agi::Color new_color) {
 		set_tag(line, blocks, tag, new_color.GetAssOverrideFormatted(), sel_start, sel_end);
-		set_tag(line, blocks, alpha, str(boost::format("&H%02X&") % (int)new_color.a), sel_start, sel_end);
+		if (new_color.a != color.a) {
+			set_tag(line, blocks, alpha, str(boost::format("&H%02X&") % (int)new_color.a), sel_start, sel_end);
+			color.a = new_color.a;
+		}
 		commit_text(c, _("set color"), sel_start, sel_end, &commit_id);
 	});
 	commit_text(c, _("set color"), -1, -1, &commit_id);