Follow-up: Use localStorage to store tableDrag.showWeight value

+++ b/core/misc/tabledrag.js
@@ -112,6 +112,7 @@ Drupal.tableDrag = function (table, tableSettings) {
+  $(window).bind('storage', $.proxy(this.toggleColumns, this));

Could use an inline comment explaining the event magic.

+++ b/core/misc/tabledrag.js
@@ -163,20 +164,21 @@ Drupal.tableDrag.prototype.initColumns = function () {
+Drupal.tableDrag.prototype.toggleColumns = function () {

Let's add some JSDoc here.

+++ b/core/misc/tabledrag.js
@@ -163,20 +164,21 @@ Drupal.tableDrag.prototype.initColumns = function () {
+  // Now hide cells and reduce colspans unless localStorage value indicates
+  // previous choice. Set a value if it is not already present.
+  if (showWeight === null) {
+    localStorage.setItem('Drupal.tableDrag.showWeight', '0');

I don't think it is a good practice to store default values on the client-side.

We should only store default overrides. In turn, that would mean to actually delete the setting when toggling the button back to its default.

+1 for patch.
+1 sun's review, especially the last part.

Also:
- this is good for WPO. Cookies make HTTP requests slower.
- browser support is solid: http://caniuse.com/namevalue-storage. Only Opera Mini is missing. I doubt this functionality works well (as in usable) in Opera Mini in the first place, so we should be okay.

+++ b/core/misc/tabledrag.jsundefined
@@ -3,6 +3,12 @@
+var showWeight = JSON.parse(localStorage.getItem('Drupal.tableDrag.showWeight'));

why use JSON.parse here?

+++ b/core/misc/tabledrag.jsundefined
@@ -163,25 +173,42 @@ Drupal.tableDrag.prototype.initColumns = function () {
+    // Reset the value to it's default.
+    localStorage.removeItem('Drupal.tableDrag.showWeight');

Should be 'its'.

Looks like a nice clean-up to me.

+1 This is very creative way of using localstorage. I like it a lot

I'm worried about raw use of localstorage API and browser support.

IE8 doesn't trigger 'storage' event, but 'onstorage'. Has been tested there? (At least I've search for 'storage' in last jquery source code without results)

Also there is a jQuery plugin http://www.jstorage.info/ that is hosted in github, so we can see what kind of fixes brings to the table, and see in the issue queue that localstorage API has some edge cases, for example errors in (ios 5 ? What about using a wrapper ? Are we using localstorage any other place in Drupal 8 ?

Thanks for the detailed answers! nothing to add
Sorry about that speculative status change, wasn't my intention to stop it ;)

Committed to 8.x. Thanks.

Committed the follow-up patch. Thanks.

When can this be roled to Drupal 7? Reason is, this cookie is breaking Varnish caching unless excluded by code in .vcl file.