Problem Summary
Seven templates hide .left_col and .right_col via $(document).ready(). Because this fires after first paint, the browser initially renders the full three-column table, then collapses the side columns. The center column snaps leftward to fill the void, generating a layout shift.
Affected Files & Patterns
Unconditional hide (always runs):
templates/default/login.tpl
templates/default/boardrules.tpl
templates/default/newuser_checkage.tpl
templates/default/newuser_signup.tpl
templates/default/lost_password.tpl
Conditional hide (runs when $mystuffNONE is true):
templates/default/editbasic.tpl
templates/default/editdisplay.tpl
{if $mystuffNONE}
<script>$().ready(function(){ $('.right_col').hide(0);$('.left_col').hide(0); });</script>
{/if}
Fix for Unconditional Templates
Remove the script line entirely. These pages should respect the forum's configured columns like every other page.
Fix for Conditional Templates
(editbasic.tpl, editdisplay.tpl) Do not hide columns after paint. When $mystuffNONE is true and those pages genuinely should not have side columns, use one of these approaches instead*
Best:
Don't render the side column <td> cells in the table structure for those pages. Modify the layout wrapper (where {$tbopen} is generated) to conditionally omit empty side columns.
Acceptable:
Apply a CSS class before paint (e.g., on <body> or the table) that sets .left_col, .right_col { display: none; }. This must be in the HTML/CSS, not jQuery after ready().
Root Cause
Whether unconditional or conditional, modifying the table layout after the browser has painted forces a recalculation. The width:100% !important on .body_col amplifies the shift because the center column aggressively expands into the collapsed space*
Recommended Action
Remove post-paint jQuery hide from all seven templates.
For editbasic.tpl and editdisplay.tpl, evaluate what $mystuffNONE means. If those pages should not have side columns, suppress them in the markup or via pre-paint CSS — never after ready().
Clear compiled template cache after changes.*
