ChatRoom: remove border when background is disabled

happy new year! here's to a great 2025!
today also marks 6 months since starting OR2006Tweaks as well
many thanks to all that contributed with bug reports/suggestions/asset mods, wouldn't have ever got as far without your help!

Author: emoose

src/overlay/chatroom.cpp

@@ -138,8 +138,12 @@ class ChatRoom : public OverlayWindow
 			// If not active then only show window if there are recent messages
 			if (!isActive && !hasRecentMessages)
 				return;
+
 			if (Overlay::ChatHideBackground)
+			{
 				ImGui::SetNextWindowBgAlpha(0.f);
+				ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
+			}
 			else
 			{
 				if (!isActive && !hasVeryRecentMessages)
@@ -157,6 +161,7 @@ class ChatRoom : public OverlayWindow
 		ImGui::SetNextWindowPos(ImVec2(borderWidth + 20, (screenQuarterHeight * 3) - 20), ImGuiCond_FirstUseEver);
 		ImGui::SetNextWindowSize(ImVec2(contentWidth - 40, screenQuarterHeight), ImGuiCond_FirstUseEver);
 
+
 		if (ImGui::Begin("Chat Messages", nullptr, !overlayEnabled ? ImGuiWindowFlags_NoDecoration : 0))
 		{
 			ImGui::SetWindowFontScale(Overlay::ChatFontSize);
@@ -230,9 +235,10 @@ class ChatRoom : public OverlayWindow
 				if (justOpened)
 					ImGui::SetKeyboardFocusHere(-1);
 			}
+			ImGui::End();
 		}
-		ImGui::End();
-
+		if (!overlayEnabled && Overlay::ChatHideBackground)
+			ImGui::PopStyleVar(); // pop border removal
 	}
 
 	~ChatRoom()