Crash when opening filter inserter gui that takes output from a chemical plant making sulfuric acid.

The mod Filter Helper (0.1.4) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event FilterHelper::on_gui_opened (ID 88)
Unknown sprite "item/sulfuric-acid"
stack traceback:
[C]: in function 'add'
FilterHelper/control.lua:21: in function 'build_sprite_buttons'
FilterHelper/control.lua:79: in function 'build_interface'
FilterHelper/control.lua:252: in function <FilterHelper/control.lua:239>

This also happens when inputting INTO an assembler making concrete, which is perhaps a better example. (Filter inserter taking output from sulfuric acid plant isn't likely in actual game)
And also in SE, using a filter inserter on a pulveriser processing core chunks (Ore output, then also water, oil, pyroflux)

I noticed your repo was public, I've made a pull request fixing the crash.

I'm experiencing a similar problem. In Py, there are many recipes that include both fluids and solids.

The mod Filter Helper (0.1.4) caused a non-recoverable error.
Please report this error to the mod author.
I had this error when placing filter inserter next to a belt and then trying to pick it up. Possibly pertinent info is the belt did have electric engines on it, which requires a fluid. Or that may not help. IDK

Error while running event FilterHelper::on_tick (ID 0)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__FilterHelper/control.lua:113: in function 'get_active_items'
FilterHelper/control.lua:334: in function <FilterHelper/control.lua:325>

Thank you Nauviax for the report, the fluid bug has been fixed in 0.1.5

Cyclomactic I will try and reproduce your report and get a fix out soon.

The mod Filter Helper (0.1.4) caused a non-recoverable error.
Please report this error to the mod author.
I had this error when placing filter inserter next to a belt and then trying to pick it up. Possibly pertinent info is the belt did have electric engines on it, which requires a fluid. Or that may not help. IDK

Error while running event FilterHelper::on_tick (ID 0)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__FilterHelper/control.lua:113: in function 'get_active_items'
FilterHelper/control.lua:334: in function <FilterHelper/control.lua:325>

I was able to reproduce and fix this in 0.1.6, thank you for the report