Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'map engine test'
2. Press the key 'n' until you get to Tristam.
3. Wait about 3 seconds '....'
4. See the fire effects that are on the ground stop animating. This same problem seems to occur on all maps but it's easiest to find in Tristam.

**Expected beha

Type of Issues (Enhancement, Error, Bug, Question)

Bug:

1. Initialize Window
2. Show it (window.Read())
3. Run window.Disable()
4. The whole desktop environment freezes, nothing is clickable anymore
5. Change to tty terminal and kill application
6. Things are normal again

Operating System

Ubuntu 16.04 LTS 64 bit

Python version

Python 3.5.2

PySi

Describe the feature you'd like
We should limit the miss angle to effectively be around 15 degrees.

Describe why do you think it is needed
Missing a target by 90 degrees just look stupid - a miss is a miss. Doesn't have to be that off 😁

https://www.reddit.com/r/warzone2100/comments/gy87wg/rookie_units_are_as_helpful_as_ever/

Add a filter to select a subset of threads.
Use SearchBox control with DelayedTextChanged event.
Hide all of the threads on the Timeline not containing specified string (should be case-insensitive).
Use space next to the Header row on the Timelne for the search box.

Code in: ThreadView.xaml.cs

Lately we decided to make rock tiles non-solid (#1609).

I found that confusing as they still looked solid to me (perhaps I was still used to playing this game with rocks being solid). The black border around the rock and the fact that it's somewhat bulky made me think it was something we could jump on :
![stone1](https://user-images.githubusercontent.com/14836881/110026977-6486e980-7cff-11eb-9

From the comment in SDL_filesystem.h:
Please call SDL_free() on the pointer when you are done with it

When building the project with MSVC, I ran into some debug heap asserts early into the program startup.
The culprit appears to be the code in m_config.c that does free(prefdir) as changing these to SDL_free(prefdir) resolved the issue.

I'm not sure what to do about `GetDefaultConfi

https://codepo8.github.io/css-fork-on-github-ribbon/

Make it more obvious that people can contribute to this list via github. I think the current text-only link in the description is easy to skip over and miss.

Context

There is a use case for creating a timer that has a variable duration. For example, if you wanted to randomly space events during a game.

Proposal

Add the ability to specify a range (min and max) of time and allow the timer to randomly choose a duration within that range.