# Changes between Initial Version and Version 1 of Ticket #1660, comment 2

Ignore:
Timestamp:
11/02/11 21:57:08 (8 years ago)
Comment:

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Unmodified
 initial Regarding the selection of multiple runs: In itemsListView_SelectedIndexChanged the method AdjustListViewColumnSizes is called every time the selected index changed. When multiselecting in the listview this event will be fired for every single item that is selected so in total N times for N selected runs. The only way to explain the really slow performance when multiselecting huge lists is that adjusting the column sizes also needs to iterate over a number of items (probably all) which results in O(N^2^) performance if all runs are selected. In itemsListView_SelectedIndexChanged the method AdjustListViewColumnSizes is called every time the selected index changed. When multiselecting in the listview this event will be fired for every single item that is selected so in total N times for N selected runs. The only way to explain the really slow performance when multiselecting huge lists is that adjusting the column sizes also needs to iterate over a number of items (probably all) which results in O(N^2^) performance if all runs are selected. I tested to remove this call which solved the performance problem. I looked into the change history. This call was added by swagner in r3829 to implement some reviewer comments. The same call was also added to the other collection views, so there was definitely a problem to be solved. Unfortunately this change is not listed on our review pages. Do you remember which reviewing issue should be solved by this change so that we can find another solution that doesn't reopen the original issue? However I couldn't find out about the original problem that should be solved with this change. I looked into the change history: The call to adjust the column sizes was added by swagner in r3829 to implement some reviewer comments. The same call was also added to the other collection views, so there was definitely a problem to be solved. Unfortunately this change is not listed on our review pages. Do you remember which reviewing issue should be solved by this change so that we can find another solution that doesn't reopen the original issue?