Add data-y attribute to datagrid td and th elements

Signed-off-by: Andrew Stein <steinlink@gmail.com>

Author: texodus

packages/perspective-viewer-datagrid/src/js/plugin/draw.js

@@ -31,8 +31,6 @@ export async function draw(view) {
     const old_sizes = save_column_size_overrides.call(this);
     const draw = this.regular_table.draw({ invalid_columns: true });
     if (!this.model._preserve_focus_state) {
-        this.regular_table.scrollTop = 0;
-        this.regular_table.scrollLeft = 0;
         this.regular_table.dispatchEvent(
             new CustomEvent("psp-deselect-all", { bubbles: false })
         );

packages/perspective-viewer-datagrid/src/js/style_handlers/table_cell/index.js

@@ -82,6 +82,9 @@ export function table_cell_style_listener(regularTable, viewer) {
                 cell_style_row_header.call(this, regularTable, td, metadata);
             }
 
+            tr.dataset.y = metadata.y;
+            td.dataset.y = metadata.y;
+            td.dataset.x = metadata.x;
             td.classList.toggle("psp-align-right", !is_th && is_numeric);
             td.classList.toggle("psp-align-left", is_th || !is_numeric);
             td.classList.toggle(

packages/perspective-viewer-datagrid/src/less/sub-cell-scroll.less

@@ -25,7 +25,8 @@ perspective-viewer-datagrid:not(.sub-cell-scroll-disabled) regular-table table,
 
     tbody tr:first-child {
         td,
-        th {
+        th,
+        &:after {
             clip-path: polygon(
                 0 var(--regular-table--clip-y, 0),
                 0 200%,