Add custom component to Static Mesh and convert to bp breaks bp editor windows

When I add a custom created ActorComponent to a SM_Door I put into the level from the starter content and then convert the door in the view-port to a blueprint it causes the Blueprint editor windows not to be viewable.

  • Create a new c++ project (Empty Project)

  • Add code based on Actor Component (TestActorComponent)

  • From Modes tab, add SM_Door to the level

  • In SM_Door details panel, Add instance of TestActorComponent to the SM_Door

  • Blueprint->Convert Selected Actor to Blueprint Class

  • Try to open Blueprint to edit, can not see BP window.

Branch: 4.15

Commit Level: a5c5b9d322ecf1e4f44b0bc4b652e98f22fcd56d

It causes the window to open but its not visible, I don’t know if its a bug where the windows extents are (0,0) - (0,0) or if its just not rendering. The only way to fix it is to delete the contents of Engine/Saved/ under UnrealEngine/. Then you can open up the blueprint editor window.

Hello ,

Thank you for reporting this. I’m not able to reproduce this behavior using the steps provided but it seems like it may have something to do with your display setup. Could you detail what your setup is like, such as how many monitors you’re using and their resolutions? Are you using Windows 10’s UI scaling feature at all?

Also, when you do this and the blueprint editor opens but is not visible, can you try hovering your cursor over the UE4 icon on the taskbar, moving to the mini-representation of the Blueprint Editor window, right-clicking and selecting Move? If you hit the arrow keys after this, it’ll lock the window to your mouse so you can drag it on screen if it is happening to show up off screen somehow.

This issue is on Linux, not Windows 10.I tried hovering over the task bar but on Linux other windows opened don’t show up as secondary windows to UE4Editor. One monitor with 1920x1200 resoultion.

First, adding a c++ component to the static mesh has no baring on this issue, its more easily reproduce-able with the SM_Door then other static meshes. Second I found the file that gets modified and what change breaks the BP editor window. it is


Here is a diff between a working config file and a broken one.

Excess information but the important lines, as far as I can tell, are WindowSize_X and WindowSize_Y, if they are both set to -10 they will not show up. Will try to investigate and see what is causing it to set the initial window size to -10,-10.

Hey -

Sorry for the late reply. I have tested again and am still not able to get a crash when adding a component to a static mesh and convert it to a blueprint. Are you still seeing this happen in 4.15.0? If so, can you provide the full callstack from the crash as well as the exact setup code / reproduction steps or a small sample project that demonstrates the crash.

Hey -

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will follow up.