diff --git a/chrome/content/zotero/lookup.js b/chrome/content/zotero/lookup.js
index 0a7431aa5..0603b7c38 100644
--- a/chrome/content/zotero/lookup.js
+++ b/chrome/content/zotero/lookup.js
@@ -206,14 +206,20 @@ var Zotero_Lookup = new function () {
 	}
 
 	this.toggleProgress = function(on) {
+		// In Firefox 52.6.0, progressmeters burn CPU at idle on Linux when undetermined, even
+		// if they're hidden. (Being hidden is enough on macOS.)
+		var mode = on ? 'undetermined' : 'determined';
+		
 		//single line
 		var txtBox = document.getElementById("zotero-lookup-textbox");
 		txtBox.style.opacity = on ? 0.5 : 1;
 		txtBox.disabled = !!on;
-		document.getElementById("zotero-lookup-progress").setAttribute("collapsed", !on);
+		var p1 = document.getElementById("zotero-lookup-progress");
+		p1.mode = mode;
 
 		//multiline
 		document.getElementById("zotero-lookup-multiline-textbox").disabled = !!on;
-		document.getElementById("zotero-lookup-multiline-progress").setAttribute("collapsed", !on);
+		var p2 = document.getElementById("zotero-lookup-multiline-progress");
+		p2.mode = mode;
 	}
 }
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index 5381a5cbc..2a1088e6e 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -1833,7 +1833,19 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 			else {
 				label.hidden = true;
 			}
-			var progressMeter = win.ZoteroPane.document.getElementById('zotero-pane-progressmeter')
+			// This is the craziest thing. In Firefox 52.6.0, the very presence of this line
+			// causes Zotero on Linux to burn 5% CPU at idle, even if everything below it in
+			// the block is commented out. Same if the progressmeter itself is hidden="true".
+			// For some reason it also doesn't seem to work to set the progressmeter to
+			// 'determined' when hiding, which we're doing in lookup.js. So instead, create a new
+			// progressmeter each time and delete it in _hideWindowZoteroPaneOverlay().
+			//
+			//let progressMeter = win.ZoteroPane.document.getElementById('zotero-pane-progressmeter');
+			let doc = win.ZoteroPane.document;
+			let container = doc.getElementById('zotero-pane-progressmeter-container');
+			let progressMeter = doc.createElement('progressmeter');
+			progressMeter.id = 'zotero-pane-progressmeter';
+			progressMeter.setAttribute('mode', 'undetermined');
 			if (determinate) {
 				progressMeter.mode = 'determined';
 				progressMeter.value = 0;
@@ -1842,6 +1854,7 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 			else {
 				progressMeter.mode = 'undetermined';
 			}
+			container.appendChild(progressMeter);
 			
 			_showWindowZoteroPaneOverlay(win.ZoteroPane.document);
 			win.ZoteroPane.document.getElementById('zotero-pane-overlay-deck').selectedIndex = 0;
@@ -1929,6 +1942,12 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 		doc.getElementById('zotero-pane-tab-catcher-top').hidden = true;
 		doc.getElementById('zotero-pane-tab-catcher-bottom').hidden = true;
 		doc.getElementById('zotero-pane-overlay').hidden = true;
+		
+		// See note in showZoteroPaneProgressMeter()
+		let pm = doc.getElementById('zotero-pane-progressmeter');
+		if (pm) {
+			pm.parentNode.removeChild(pm);
+		}
 	}
 	
 	
diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index e814727cf..e41b56855 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -2256,10 +2256,10 @@ var ZoteroPane = new function()
 			return;
 		}
 		var spinner = document.getElementById('zotero-tb-search-spinner');
-		spinner.style.visibility = 'visible';
+		spinner.style.display = 'inline';
 		var searchVal = search.value;
 		yield this.itemsView.setFilter('search', searchVal);
-		spinner.style.visibility = 'hidden';
+		spinner.style.display = 'none';
 		if (runAdvanced) {
 			this.clearItemsPaneMessage();
 		}
diff --git a/chrome/content/zotero/zoteroPane.xul b/chrome/content/zotero/zoteroPane.xul
index b86764fc1..e02d0d624 100644
--- a/chrome/content/zotero/zoteroPane.xul
+++ b/chrome/content/zotero/zoteroPane.xul
@@ -170,7 +170,7 @@
 							<description>&zotero.lookup.description;</description>
 							<vbox id="zotero-lookup-singleLine">
 								<stack>
-									<progressmeter id="zotero-lookup-progress" mode="undetermined" collapsed="true"/>
+									<progressmeter id="zotero-lookup-progress" mode="determined"/>
 									<textbox id="zotero-lookup-textbox"
 										onkeypress="return Zotero_Lookup.onKeyPress(event, this)"
 										oninput="Zotero_Lookup.onInput(event, this)"
@@ -182,7 +182,7 @@
 								<textbox id="zotero-lookup-multiline-textbox" onkeypress="return Zotero_Lookup.onKeyPress(event, this)" multiline="true" rows="5" wrap="off" flex="1"/>
 								<hbox align="start" id="zotero-lookup-buttons" class="zotero-button-clear-image">
 									<button label="&zotero.lookup.button.search;" align="start" oncommand="Zotero_Lookup.accept(document.getElementById('zotero-lookup-multiline-textbox'))"/>
-									<progressmeter id="zotero-lookup-multiline-progress" mode="undetermined" collapsed="true" flex="1"/>
+									<progressmeter id="zotero-lookup-multiline-progress" mode="determined" flex="1"/>
 								</hbox>
 							</vbox>
 						</vbox>
@@ -207,7 +207,7 @@
 					<toolbarseparator/>
 					<toolbarbutton id="zotero-tb-advanced-search" class="zotero-tb-button" tooltiptext="&zotero.toolbar.advancedSearch;" command="cmd_zotero_advancedSearch"/>
 					<spacer flex="1"/>
-					<image id="zotero-tb-search-spinner" class="zotero-spinner-14" style="visibility: hidden"/>
+					<image id="zotero-tb-search-spinner" class="zotero-spinner-14" style="display: none"/>
 					<textbox id="zotero-tb-search" type="search" timeout="250"
 							onkeypress="ZoteroPane_Local.handleSearchKeypress(this, event)"
 							oninput="ZoteroPane_Local.handleSearchInput(this, event)"
@@ -611,9 +611,10 @@
 			<deck id="zotero-pane-overlay-deck" flex="1">
 				<box id="zotero-pane-progress" flex="1" align="center" pack="center">
 					<box style="background: white; border-radius: 1px; box-shadow: gray 4px 6px 4px;" width="300" height="30">
-						<vbox style="padding:10px" flex="1">
+						<vbox id="zotero-pane-progressmeter-container" style="padding:10px" flex="1">
 							<label id="zotero-pane-progress-label"/>
-							<progressmeter id="zotero-pane-progressmeter" mode="undetermined"/>
+							<!-- See note in Zotero.showZoteroPaneProgressMeter()
+							<progressmeter id="zotero-pane-progressmeter" mode="undetermined"/> -->
 						</vbox>
 					</box>
 				</box>