jupyrdfGH-116: Add buffer to SelectMultiple (jupyrdf#117)

* jupyrdfGH-116: Add buffer to widget.

CONTRIBUTING.md

@@ -91,7 +91,8 @@ doit all
   anaconda-project run --env-spec build twine upload dist/ipyradiant*
   ```
 
-> Note: If you have issues with twine (on windows), you may need to manually activate the build environment (`conda activate envs/build`) and run the twine commands.
+> Note: If you have issues with twine (on windows), you may need to manually activate
+> the build environment (`conda activate envs/build`) and run the twine commands.
 
 - Check hashes on `pypi` after the upload completes
 - Complete `conda-forge` tasks
@@ -100,7 +101,8 @@ doit all
   - update `recipe/meta.yml` (version and sha for tar)
   - submit PR to conda-forge feedstock (go through checklist). DO NOT PUSH DIRECTLY
   - wait for CI, merge (requires write permissions) and wait for CI again
-  - once CI is done, the new package version should be visible on [conda-forge][conda-forge-ipyradiant]
+  - once CI is done, the new package version should be visible on
+    [conda-forge][conda-forge-ipyradiant]
 
 [radiance-si-units]: https://en.wikipedia.org/wiki/Radiance#SI_radiometry_units
 [conda-forge-ipyradiant]: https://anaconda.org/conda-forge/ipyradiant

src/ipyradiant/visualization/cytoscape/__init__.py

@@ -1,7 +1,11 @@
 # Copyright (c) 2021 ipyradiant contributors.
 # Distributed under the terms of the Modified BSD License.
 
-__all__ = ["CytoscapeViewer", "CytoscapeVisualizer", "InteractiveViewer"]
+__all__ = [
+    "CytoscapeViewer",
+    "CytoscapeVisualizer",
+    "InteractiveViewer",
+]
 
 from .app import CytoscapeVisualizer
 from .interactive import InteractiveViewer

src/ipyradiant/visualization/cytoscape/interactive.py

@@ -395,7 +395,7 @@ def update_rdf_graph(self, change):
         # set options, value, and row counts
         self.type_selector.options = select_options
         self.type_selector.value = tuple(uri for _, uri in select_options)
-        self.type_selector.rows = len(select_options)
+        self.type_selector.rows = len(select_options) + 1
 
         # build options for the predicate MultiSelect
         select_options = []
@@ -406,7 +406,7 @@ def update_rdf_graph(self, change):
         # set options, value, and row counts
         self.predicate_selector.options = select_options
         self.predicate_selector.value = tuple(uri for _, uri in select_options)
-        self.predicate_selector.rows = len(select_options)
+        self.predicate_selector.rows = len(select_options) + 1
 
         color_classes = self.assign_css_classes()
         self.apply_node_styling(change=None)