Bugfix: Add the missed keyReleaseEvent method in QtViewerDockWidget

[ksofiyuk]

Description

I noticed that callbacks do not get key release events when the focus is not on the canvas but they continue to receive key press events. You can easily reproduce the issue by running examples/custom_key_bindings.py and then clicking, for example, on the layer in the layer list, the hello callback (on w key) no longer receives key release events after that.

The issue is cause by the missed keyReleaseEvent in QtViewerDockWidget.

References

Type of change

• Bugfix (non-breaking change which fixes an issue)

How has this been tested?

• I tested it manually

Final checklist:

• My PR is the minimum possible work for the desired functionality
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
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[codecov]

Codecov Report

Merging #5746 (0ffcddc) into main (95356e4) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main    #5746   +/-   ##
=======================================
  Coverage   89.83%   89.84%           
=======================================
  Files         608      608           
  Lines       51881    51883    +2     
=======================================
+ Hits        46608    46613    +5     
+ Misses       5273     5270    -3     

Impacted Files	Coverage Δ
napari/_qt/widgets/qt_viewer_dock_widget.py	96.06% <50.00%> (-0.53%)	⬇️

... and 3 files with indirect coverage changes

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[alisterburt]

@ksofiyuk thanks for digging here - I have often wanted this to work but there is some hidden complexity here so I'd like opinions from some others before merge

from skimage import data
import napari

blobs = data.binary_blobs(
    length=128, blob_size_fraction=0.05, n_dim=2, volume_fraction=0.25
).astype(float)

viewer = napari.view_image(blobs, name='blobs')
viewer.add_points([64, 64, 64], size=20)

@viewer.bind_key('Up')
def reject_image(viewer):
    msg = 'this is a bad image'
    viewer.status = msg

@napari.Viewer.bind_key('w')
def hello(viewer):
    viewer.status = 'hello world!'
    yield
    viewer.status = 'goodbye world :('
napari.run()

When the layer list is selected it can be navigated using the Up/Down arrow keys - I think this is default Qt behaviour. In this example, our callback is still run when we press the Up key even if we are trying to navigate the layer list

I also tested the callback attached to 'w' and am happy to report than when editing text fields like the layer name and pressing w this callback is not called so this problem is not everywhere and might be limited to Up/Down on list widgets

Questions:

• do we think only Up/Down are affected by this?
• if the above is true, is there an easy way to blacklist callbacks attached to just those keys?

[ksofiyuk]

In this example, our callback is still run when we press the Up key even if we are trying to navigate the layer list

@alisterburt Thank you for being mindful about possible issues. However, this PR doesn't actually affect it because it simply adds the omitted the key release event; the key press event is already there (for years since 2019 judging by the commits history) and the described behavior with the Up key is happening with the current main branch.

All the possible pitfalls that you mentioned should already be present as most callbacks only care about the key press event.

[alisterburt]

interesting - I'm now trying to work out what exactly hasn't been working for me when the canvas is not in focus 😆 thank you for clarifying, in this case I am happy for this to be merged as is