Bug Report for 1.17.6! Black Screen on Turn Dialog, and "Undo" not working

[Shield]

These bugs are exactly what they sound like, but I'll elaborate. The first is that, when I have "Turn Dialog" (that box that says "It's now (Player)'s turn" at the beginning of every player turn) enabled, the map around it turns completely black until the dialog box is dismissed. The top bar and sidebar are unaffected, but the map is utterly blackened. This is a bug I have also noticed in previous versions of Wesnoth (I forget which one I first saw it in, possibly in the 1.13 or 1.14 branch? maybe later), but had not reported because I guess I assumed somebody else would say/do something.
Here is a screenshot of the bug in action, in the Tutorial campaign. The bug is also visible in every other campaign I play-- both mainline and UMC-- as well as MP content of both kinds as well.

The game has been doing this for *years*

Also worthy to mention is that this bug has gotten worse over the years since whenever it was I first noticed it. In addition to turning the map black and thus breaking immersion, now it also lingers a while. When the turn dialog box is dismissed, the map will remain black except for animated water hexes, and a few units and areas around them. Hovering over any unit dismisses most of the black covering the hexes, blackened hexes will "uncover" from the hex they're obscuring when hovered over with the cursor, and all of the blackness will go away when either hovered over with a cursor enough, or the map is scrolled away from it. This bug does not impact actual gameplay, and no aspect of screen blackening (aside from like, maybe the map being dark at the beginning anyway for a few seconds before opening cutscenes, before the scenario really starts... possibly a loading thing? I can't remember this in older versions) appears at all when "turn dialog" is disabled.
Here are some more screenshots, of this newer and more inconvenient aspect of the bug, in the Tutorial and Caves of the Basilisk:

As you can see, gameplay is still possible, just obscured.

Not exclusive to the Tutorial.

This is a bug that seems to me to be glaringly obvious, but since I have seen it in Wesnoth for the last few years and it has yet to go away, I can only assume that either anyone else who's seen it assumed someone else would report it, or less people play with "show Turn Dialog" enabled than I thought. I'm reporting this now before I forget, and before it gets any worse.

And now, for the more direly serious bug: "Undo" functionality being broken.
I try to press the "U" key, and the game simply does not Undo. I even checked my Preferences to make sure the hotkey was still the same, and it was, but it still refused to function. I tried this both yesterday with the Tutorial, and today with Caves of the Basilisk.
I'm not sure if I can describe how to "recreate" this one, it just kind of... is. But just in case, here's the replay file of the Tutorial's 2nd scenario. I try to Undo at Galdrad's suggestion on turn 2, and on turn 7 (you can see me quickly step an Archer into the water, and then back into the forest-- me confirming that undoing moves wasn't possible with the hotkey and I had to either go back a turn or hope I had enough move points left).

Tutorial-Wesnoth Tutorial — Part II replay 20220802-092702.gz

(24.73 KiB) Downloaded 31 times

Operating System: Windows 10 Home, version 21H1
Hardware: HP Slim Desktop 450-a24, 64 bit
Configured Language: US English
Build Information: The Battle for Wesnoth version 1.17.6 x86_64
Running on Microsoft Windows 10 21H1 (10.0.19043) x86_64
Distribution channel: SourceForge

Game paths
==========

Data dir: C:\Program Files\Battle for Wesnoth 1.17.6
User config dir: C:\Users\USER\Documents\My Games\Wesnoth1.17
User data dir: C:\Users\USER\Documents\My Games\Wesnoth1.17
Saves dir: C:\Users\USER\Documents\My Games\Wesnoth1.17\saves
Add-ons dir: C:\Users\USER\Documents\My Games\Wesnoth1.17\data\add-ons
Cache dir: C:\Users\USER\Documents\My Games\Wesnoth1.17\cache

Libraries
=========

Boost: 1.79
Lua: 5.4.4
OpenSSL/libcrypto: 1.1.1o (runtime 1.1.1o)
Cairo: 1.17.6 (runtime 1.17.6)
Pango: 1.50.7 (runtime 1.50.7)
SDL: 2.0.22 (runtime 2.0.22)
SDL_image: 2.0.5 (runtime 2.0.5)
SDL_mixer: 2.0.4 (runtime 2.0.4)

Features
========

Lua console completion: yes
Win32 notifications back end: yes

Current video settings
======================

SDL video drivers: [windows] dummy
Window size: 1920x1061
Game canvas size: 1920x1061
Final render target size: 1920x1061
Screen refresh rate: 60

Current audio settings
======================

SDL audio drivers: [wasapi] directsound
Number of channels: 2
Output rate: 48000 Hz
Sample format: signed 16 bit little-endian
Sample size: 4096 bytes

Installed add-ons
=================

An_Orcish_Incursion: 1.0.3

Recreating the bug: Having "Enable Turn Dialog" enabled in the preferences, playing any scenario long enough to show the turn dialog at least once.

.... To note to the above, I normally use Wesnoth in 1920x1080 resolution, but it decreased to 1920x1061 because I went to "windowed" mode in order to copy-paste things faster. I do not know if running the game in windowed or fullscreen mode makes a difference in these errors. I have not tried the latest stable version of Wesnoth, the latest version I'd tried before this was 1.16.2, which I can't remember much about, but to my knowledge did not have the problem with the Undo hotkey.
I'm not sure there's more to say at the moment, but I can provide more info if necessary and possible. I am constantly forgetting to report the black screen bug, and I almost lost this entire post to an unexpected computer restart, so I'm posting now before the universe prevents me from reporting yet again somehow. Hoping this gets taken care of, because it's been legitimately discouraging me from playing Wesnoth for a while because I'm so used to the Turn Dialog and hate to have to turn it off.

[Lord-Knightmare]

Can you please file a bug report here: https://github.com/wesnoth/wesnoth/issues and linking this forum thread in it?

[Shield]

Will do! I'd read that that was the recommended approach, but since I lacked a GitHub account, I reported it here... I have now quickly thrown together a GitHub account, and filed a report on this bug as my first post there. I hope it's sufficient and proper enough (my computer freezing as I was about to post didn't help, I had to retype the whole thing... truly, reporting this bug has always been a struggle), and also that the problem can be reproduced and fixed easily.