handle backspace input from table selection

svelte/src/datum-editor.svelte

@@ -145,6 +145,17 @@ example within the `<TableViewer />` or `<ExpressionEditor />`.
       // Cancel edit before blurring, or else the table will try to commit it.
       on_cancel_edit?.();
       on_restore_focus?.();
+    } else if (ev.key === "Backspace") {
+      if (
+        editor_state &&
+        ["Dropdown", "Numeric", "Text", "Uuid"].includes(
+          current_presentation.t ?? "",
+        ) &&
+        editor_state.text_value === ""
+      ) {
+        editor_state.is_null = !editor_state.is_null;
+        handle_input();
+      }
     } else if (
       current_presentation.t === "Dropdown" &&
       filtered_dropdown_options.length > 0

svelte/src/table-viewer.webc.svelte

@@ -393,7 +393,7 @@
       !ev.altKey &&
       !ev.ctrlKey &&
       !ev.metaKey &&
-      /^[a-zA-Z0-9`~!@#$%^&*()_=+[\]{}\\|;:'",<.>/?-]$/.test(ev.key)
+      /^([a-zA-Z0-9`~!@#$%^&*()_=+[\]{}\\|;:'",<.>/?-]|Backspace)$/.test(ev.key)
     ) {
       const sel = selections[0];
       if (sel) {
@@ -401,6 +401,7 @@
           lazy_data.fields[sel.coords.field_idx].field.presentation,
         );
         datum_editor?.focus();
+        try_sync_edit_to_cells();
       }
     } else if (ev.key === "Enter") {
       if (ev.shiftKey) {