Just to quote the answer here (It helps if that forum post is deleted or address is changed) :
/**
* Override to fix box-sizing problem in chrome latest versions
*/
if (!Ext.isDefined(Ext.webKitVersion)) {
Ext.webKitVersion = Ext.isWebKit ? parseFloat(/AppleWebKit\/([\d.]+)/.exec(navigator.userAgent)[1], 10) : NaN;
}
/*
* Box-sizing was changed beginning with Chrome v19. For background information, see:
* http://code.google.com/p/chromium/issues/detail?id=124816
* https://bugs.webkit.org/show_bug.cgi?id=78412
* https://bugs.webkit.org/show_bug.cgi?id=87536
* http://www.sencha.com/forum/showthread.php?198124-Grids-are-rendered-differently-in-upcoming-versions-of-Google-Chrome&p=824367
*
* */
if (Ext.isWebKit && Ext.webKitVersion >= 535.2) { // probably not the exact version, but the issues started appearing in chromium 19
Ext.override(Ext.grid.ColumnModel, {
getTotalWidth : function (includeHidden) {
if (!this.totalWidth) {
var boxsizeadj = 2;
this.totalWidth = 0;
for (var i = 0, len = this.config.length; i < len; i++) {
if (includeHidden || !this.isHidden(i)) {
this.totalWidth += (this.getColumnWidth(i) + boxsizeadj);
}
}
}
return this.totalWidth;
}
});
Ext.onReady(function () {
Ext.get(document.body).addClass('ext-chrome-fixes');
Ext.util.CSS.createStyleSheet('@media screen and (-webkit-min-device-pixel-ratio:0) {.x-grid3-cell{box-sizing: border-box !important;}}', 'chrome-fixes-box-sizing');
});
}
This is a override, so just paste this in a separate file as ' lockingGridColumnLinesAlignmentFix.js ' (may be !) and include this file after ext libraries and before your ' app.js ' (in which you have written code for locking grid).